diff --git a/2021/4/.gitignore b/2021/4/.gitignore
new file mode 100644
index 0000000..2f7896d
--- /dev/null
+++ b/2021/4/.gitignore
@@ -0,0 +1 @@
+target/
diff --git a/2021/4/Cargo.lock b/2021/4/Cargo.lock
new file mode 100644
index 0000000..e92c02c
--- /dev/null
+++ b/2021/4/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day4"
+version = "0.1.0"
diff --git a/2021/4/Cargo.toml b/2021/4/Cargo.toml
new file mode 100644
index 0000000..8842130
--- /dev/null
+++ b/2021/4/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "day4"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/2021/4/input b/2021/4/input
new file mode 100644
index 0000000..5e4d907
--- /dev/null
+++ b/2021/4/input
@@ -0,0 +1,601 @@
+69,88,67,56,53,97,46,29,37,51,3,93,92,78,41,22,45,66,13,82,2,7,52,40,18,70,32,95,89,64,84,68,83,26,43,0,61,36,57,34,80,39,6,63,72,98,21,54,23,28,65,16,76,11,20,33,96,4,10,25,30,19,90,24,55,91,15,8,71,99,58,14,60,48,44,17,47,85,74,87,86,27,42,38,81,79,94,73,12,5,77,35,9,62,50,31,49,59,75,1
+
+78 27 82 68 20
+14  2 34 51  7
+58 57 99 37 81
+ 9  4  0 76 45
+67 69 70 17 23
+
+38 60 62 34 41
+39 58 91 45 10
+66 74 94 50 17
+68 27 75 97 49
+36 64  5 98 15
+
+17 50 13 53 20
+68 57 76 10 86
+ 2 91 67 27 11
+94 70 84 69 25
+32 90 45 75 41
+
+71 84 42 49 81
+26 40 24 73 18
+41 37 19 25 75
+76 63 48 56 55
+85 51 29 88 23
+
+27 10 11 75 59
+61 96 44 58 64
+24 68 90 60 87
+28 55 34 80  9
+41 98 91 78 62
+
+91 95 70 64 30
+34 43 32 16 57
+49 80 87 51 62
+61 10  8 75 21
+85 66  2 55 56
+
+50  4 11 58 48
+30 10 57 16 95
+93 96 68 92 81
+94 17 69 86 79
+52 34 99  6 19
+
+ 2 16 50 26 84
+97 24 32 51  8
+70  0  3 52  9
+ 1 59 43 64 80
+22 23 17 92 88
+
+84  7 37 71 81
+80 97 17 94  9
+27 95 39 25  5
+98 46 58 77  2
+60  1 73 23 18
+
+ 1 14 67 20 48
+75 51 36 87 73
+57 84 74 47 19
+89  8 13 50 24
+61 12 65 46 83
+
+82 87  8  9 85
+16 22 98 91 55
+26 69 42 11 93
+65 15  2 63 43
+71 37 28 88 12
+
+59  7 51  1 43
+17 45 15 96 93
+49 88 79 84 92
+40 36 25 18 22
+70 57 34 62  6
+
+ 1 18  5 47 46
+12 27 24 40  2
+53 54 20 14 42
+15 51 26 58  9
+31 92 34 74  7
+
+41 84 14 32  8
+38  1 60 22 88
+64 70 10 91 97
+94 90 65 54 50
+ 7 58 18 87 33
+
+93 25 26 71 42
+86 85 61 32 51
+20 88 67 35 29
+46 28 92  9 16
+34 30 97 91 44
+
+34 88 90 99 83
+22 24  4 25 18
+51 41 29 53 72
+75 42 66 98 79
+74  7  0 73 33
+
+99 24 44 83 47
+ 2 21 94 35  4
+96 87 31  1 22
+67  3 37 43 46
+85 55 10  6 80
+
+ 4 75 29 54 15
+66 17 89 98 27
+46  5 64  3 22
+97 50  0 51 52
+26 39 30 32 48
+
+39 17 46 48 63
+52 13 98 40 91
+14 80 28 23 60
+90 88 15 89 74
+56  7  2 41 58
+
+82 51  6  7 22
+87  9 60 63 95
+80  0  5  8 77
+85  3 68 84 39
+15 45 31 55 26
+
+48 82 38 29 55
+87 46 79 61 51
+ 1 97 69 91 83
+35 89 45 59 39
+43 28 21 44 24
+
+71 97 34 43 23
+44 65 92 90 31
+74 87 54 79 93
+55 88 66 12 53
+14 56 17 52 83
+
+91 33 20 59 67
+71 78 15 94 68
+ 8 90 72 57 36
+27 40 92  1 44
+18 80  7 32 19
+
+67 20 94 89 10
+85 78 70 35  0
+87 66 75 73 23
+36  8 17 83 21
+40 52 93 62 96
+
+ 8 37 66 26 63
+ 7 90 21 18 33
+31 56 81 77 55
+34 15 19 27 57
+13 85  0 59  4
+
+67 77 48 26  6
+31 72 89 76 45
+66  4  7 43 78
+15 53 81 85 70
+ 0 10 40 30 94
+
+79 37  8 29 27
+41 14 12 99 28
+75 40 30 25 77
+36 78 39 32 11
+91 58 17 96 51
+
+36  8 35 30 51
+28 61  4 95 67
+29 69 32 80 48
+55 63 98 10 22
+27 87 83 62 21
+
+24 36 52 72 16
+53  1  4 96 37
+31  7 69 47 57
+38 97  3 26 59
+74 14 29 32 40
+
+ 8 73 68 62 38
+43 92 15 69 46
+56 58 48 28 44
+25 64 13 50 97
+66 34 21 49 10
+
+63 41 71 22 18
+56 82 95 60 35
+53 48 79 30 86
+17 51 57 70 27
+75 66 42 32 43
+
+60 59 40 42 90
+65 22 43  0 49
+82 96 29 52 73
+67 17 20 53 24
+72  5 91 50 85
+
+94 47  2 93 74
+90 10 27 17  5
+92 26 28 77 88
+69 43 33 19 53
+34 50 54 36 60
+
+73 36 90 50 37
+11 80 81 93 74
+78 56 86  6 39
+15 94  7 91 42
+33  8 64 40 28
+
+73 37 57 65  0
+64 26 52 79 69
+15 41  3  2  1
+71 48  8 43 31
+ 5 93 86 42 27
+
+59 35 19 17 83
+15 93 53  2  4
+26 51 85 71 22
+31 52 74 12 57
+70 40 68 39 24
+
+ 3  6 45 81 20
+82 30 15 62 80
+21 70 56 23 32
+68 19 50 16 14
+46 89 72 59 40
+
+17 27 72 36 12
+55 30  6 88 69
+34 91 87 45 82
+48 15 18 21  7
+44  4 81 14 93
+
+55 84 58 24 53
+99 44 88 54 37
+ 2 56 57 50 35
+13 90 26 30 96
+ 7 97 12 19 71
+
+31 26 87 54 76
+68 24 20 27 98
+53 75 15 95  8
+63  2 45 50  9
+49 17 88 55  1
+
+91 78 45 26 30
+63 95 67 60 58
+34 39 44 20 11
+38 29 73 22 80
+56 12 77 37  4
+
+24 18 65 21  6
+76 45 85  2 78
+67 69 55 91 57
+96 61 39 36 83
+ 8 54 12 38 70
+
+33 71 24 82 84
+53 32 45  9 34
+89 28 30 42 96
+49 95 69 51 12
+80 41 31 48 75
+
+40 60  0 92 13
+87  9 45 98 77
+14 91 35  1 95
+79 39 19 89 51
+61 56  8 97 32
+
+89 70  2 81 34
+21 59 39 84 64
+28 94 97 29 30
+35 27 99 32 55
+23 47 14 88  0
+
+46 14 92 49 94
+90 80  2 65 30
+54 32 35 56 27
+29 55 97 39 37
+81 72 47 66 42
+
+53  1  0 34 82
+26 28 30 65 41
+17  4 57 49 40
+84 46 27 35 91
+56 38 20 81 86
+
+10 31 98 66 22
+87 99 24 34 93
+ 7 95 28 78 73
+61 25 14  5  1
+42 85 16 47 43
+
+92 43  9 68 40
+41 65 18 69 89
+35 88 62 67 75
+64  4 17 42 93
+78 33 94 87 81
+
+18 61 10 19 87
+46 99 55  3 28
+16 41 45 39 27
+ 8 13 43 64 52
+23 34 47 11 92
+
+21 59 74 36 38
+81 29 79 80 44
+84 30 37 62 57
+69 82 60 10 52
+ 7 55 93 12  0
+
+37 23 52  2 94
+19 96  8 68 29
+99 57 53  9 48
+62 11 35 95 98
+93 72 58 16 36
+
+80 53 82 29 76
+77 17 85 62 81
+34 92 25 55 20
+91 39 23 50 31
+64 37 79 96  2
+
+40  5 57 36 14
+91 53 56 73 27
+11 55 74  7  9
+90 58 12 22 26
+82 38 59 97 85
+
+54 79 75  0 30
+ 7 15 26 84 40
+91 76 42  3 19
+65 77 53 21 67
+45 50  2 14 46
+
+23 51 40 13 72
+54 61 59 18 14
+ 0 41  5 24 82
+73 11 46 36 17
+16 28 25 60  4
+
+85 42 22 54 18
+ 3 27 12 15 99
+13 26 89 93 76
+23 87 77 64 25
+ 9 17 74 57 81
+
+47 64 85 69 89
+59 17  4 83 88
+80 70 53  7 67
+73 18 81 44 30
+45 37 90 57  3
+
+72 48 35 39 31
+44 85 91 52 46
+73 61 68 66 12
+74 95 76 75 36
+83 21 15  2 10
+
+63 82 95 31 51
+93  3 53 15 70
+ 0 36 44 19  5
+11 17 62 55 83
+80 91  4 18 66
+
+44  8 45 90 64
+30 33  9 27 47
+68 53 81 77 35
+63  4 82 80 67
+ 3 28 66 22 43
+
+48 86 57 16  7
+69 51 11  8 61
+25 12 43 88 71
+83 36 31 77  5
+50 21  9 76 63
+
+27 39  6 87 49
+16 66  3 25 10
+ 7 70  8 94 42
+95 20 55  9 29
+ 0 46 36 79 18
+
+27 21 36 14 79
+23 48 56 74 94
+18 99 73 93 32
+98 77 37 35 69
+43 34 63 59  9
+
+27 96 78 94 20
+34  5 49 84 99
+68 74 21 57  1
+93 85 29 47 65
+54 97 42 70 40
+
+29 28 64 26 46
+39 48 13 51  2
+42 91 96 93 66
+12 60 70  8 24
+18 21 83 56 45
+
+64 43 76 40 97
+30 10 22 84 53
+51 13 68 93 15
+75 27 18 39 82
+62 61 91 12 88
+
+72  6 61 10 45
+65 62 57  2 91
+30 24 76 42 69
+32 36 43 63 75
+92 44 58 82 49
+
+30 39 58 75 76
+62 53 59 70 97
+29 31 54 27 89
+90 32 37 86  1
+ 7 34 42 61 91
+
+98 94 10 72 26
+96 78 69 77 44
+45  5 88 42 73
+74 91 25 22 99
+16 79 60 71 37
+
+44 33 34 27 87
+46 89 75 37  4
+71 63 16 35 17
+83 99 28 51 97
+66 86 14 61  9
+
+ 2 54  7 32 79
+33 36 37 35 81
+25 50 84 59 21
+18 16 48 26 15
+94 73 61 67 44
+
+18 34 66 57 31
+74 92 71 59 19
+36 94 16 80 24
+35 54 58 87 64
+73 90 41 49 88
+
+74  5 57 40 21
+61 11 50 80 66
+35 58 52 10 56
+92 67 82 46 72
+32 18 33 34 55
+
+66 79 27 24 46
+98  4 30 80 49
+19 23 68 18 90
+41 91 83 63 77
+84 12  8 10 21
+
+23 47 58  5 20
+30 32 61  6 28
+24 11  8 33 10
+52 93 95  0 45
+22 27  3 82 40
+
+11 51 47 83 38
+28 85  9 10 48
+80 60 46 55 32
+89 14 90 71 50
+ 0 65 24 40 19
+
+12  2 37 62 93
+78 69 53 43 33
+85 76 26 21 92
+36 54 89 46 91
+29 18 72  9 51
+
+82 36 47 95 30
+65  2 98 92 12
+93 73 44 48  6
+31 74 62 27 42
+32 13 11 99 50
+
+89 31 94  1 78
+77 24 46 64 26
+11 16 28 30 45
+80 22  5  8 52
+32 38 76 65 90
+
+92 96 35 86 51
+47 75 17 87 30
+43 29 55 50 11
+77 99 48 24 20
+37  7 91 23  8
+
+26 12 82 95 78
+41 65 80 53 44
+75 43 32 46 84
+63 99 69 45 88
+56 48 87 38 49
+
+ 8 87 21 27 15
+84 44 26 61 82
+10 66 29 95 65
+ 4 86 38 91 28
+14 49 22 52 54
+
+27 43 13 35 33
+20 66 77 70 31
+ 5 17 94 98 83
+11 22 39 55 75
+53 61 46 38 89
+
+84 49 52 32 51
+90 46 97 91 54
+ 2 42 65 10 25
+80 77 31 81 16
+58 17 15 26 55
+
+19 83 57 21 95
+ 4 29 11 64  0
+17 63 13 27 58
+14 96 43 22 56
+97 84 81 67 94
+
+47 49  4 70 65
+60 88  9 77  3
+63 72 33 50 97
+68 84 98 78 89
+10 79 25 24 54
+
+81 70 39 73 11
+86 30 38 14 91
+ 9 18 72 21 24
+54 83 80 78 66
+23 93 36 31 53
+
+34 58 18 69 28
+57 70 54 50 64
+35 36  4 56 72
+32 16 45 33 17
+83 60 39 22 47
+
+31 73 56 21 63
+66 14 42 45 80
+60 57 47 36 78
+93 75 44 22 11
+68 89 58 88 17
+
+74 16 65 13 45
+86 20  6 34 15
+70 46 59 75 57
+28 62 67 71 98
+77 63 25 61 64
+
+71 20 42 65 47
+29 80 53 78 99
+70 57 18 45 32
+86 46 35 77 26
+15 91 93 55 67
+
+27 16 31 41 42
+77 34 10 90 18
+28 99 44 20 68
+98 82  3 75 62
+88 85 47 17 71
+
+31 95 98 60 93
+80 81 23 35 70
+ 4 57 38 69 76
+18  0 41 86 54
+47 26 90 65 39
+
+79 86 59 66 50
+49 64 65 95  6
+90 67 36 32 46
+10 20 25 27  1
+87 21 17 78 13
+
+16  8 95 35 43
+14  0 72 89 68
+52 11 12 67 25
+63 64 13 32 15
+53 98 55 81 75
+
+51 85 15 91 10
+24 68 80 22  8
+55 18 36 30 66
+27 21 46 63 26
+81  5 14  2 13
+
+71 39 19 40 69
+58 70 65 46 78
+98 14 59 94 60
+12 55 68 91  0
+18 35 25 61 86
+
+85 74 56 43 44
+98 78 17 95  8
+70 30 66 55 94
+57 62 82 49 77
+61 32 97 88 58
+
+23  1 53 65 30
+45 15  9 26 28
+ 2 21 42 27 12
+84 68 71 19 13
+58 57 35 77 14
\ No newline at end of file
diff --git a/2021/4/src/main.rs b/2021/4/src/main.rs
new file mode 100644
index 0000000..15791af
--- /dev/null
+++ b/2021/4/src/main.rs
@@ -0,0 +1,138 @@
+use std::fs;
+
+fn main() {
+    part_one();
+    part_two();
+}
+
+fn part_one() {
+    let contents = fs::read_to_string("input")
+        .expect("Something went wrong reading the file");
+   
+    let mut groups: Vec<String> = contents
+        .split("\n\n")
+        .map(|x| x
+            .to_string()
+        )
+        .collect();
+
+    let bingo_nums: Vec<i32> = groups
+        .remove(0)
+        .split(',')
+        .map(|x| x
+            .parse::<i32>()
+            .unwrap()
+        )
+        .collect();
+
+    let mut boards: Vec<Vec<Vec<i32>>> = groups.iter().map(|group| group
+        .split('\n')
+        .map(|x| x
+            .split(' ')
+            .filter(|x| *x != "")
+            .map(|x| x
+                .parse::<i32>()
+                .unwrap()
+            )
+            .collect()
+        )
+        .collect()
+    ).collect();
+
+    for num in bingo_nums {
+        boards = boards
+            .into_iter()
+            .map(|board| board
+                .into_iter()
+                .map(|row| row
+                    .into_iter()
+                    .map(|x| if x == num { -1 } else { x })
+                    .collect()
+                )
+                .collect()
+            )
+            .collect();
+
+        let winning_boards: Vec<&Vec<Vec<i32>>> = boards.iter()
+            .filter(|board|
+                board.iter().filter(|row|
+                    row[0] == -1 && row[1] == -1 && row[2] == -1 && row[3] == -1 && row[4] == -1
+                ).collect::<Vec<&Vec<i32>>>().len() > 0 ||
+                [0, 1, 2, 3, 4].into_iter().filter(|column|
+                    board[0][*column] == -1 && board[1][*column] == -1 && board[2][*column] == -1 && board[3][*column] == -1 && board[4][*column] == -1
+                ).collect::<Vec<usize>>().len() > 0
+            ).collect();
+
+        if winning_boards.len() > 0 {
+            let sum: i32 = winning_boards.into_iter().take(1).flatten().flatten().filter(|x| **x != -1).sum();
+            println!("Part 1, final score: {}", sum * num);
+            break;
+        }
+    }
+}
+
+fn part_two() {
+    let contents = fs::read_to_string("input")
+        .expect("Something went wrong reading the file");
+   
+    let mut groups: Vec<String> = contents
+        .split("\n\n")
+        .map(|x| x
+            .to_string()
+        )
+        .collect();
+
+    let bingo_nums: Vec<i32> = groups
+        .remove(0)
+        .split(',')
+        .map(|x| x
+            .parse::<i32>()
+            .unwrap()
+        )
+        .collect();
+
+    let mut boards: Vec<Vec<Vec<i32>>> = groups.iter().map(|group| group
+        .split('\n')
+        .map(|x| x
+            .split(' ')
+            .filter(|x| *x != "")
+            .map(|x| x
+                .parse::<i32>()
+                .unwrap()
+            )
+            .collect()
+        )
+        .collect()
+    ).collect();
+
+    for num in bingo_nums {
+        boards = boards
+            .into_iter()
+            .map(|board| board
+                .into_iter()
+                .map(|row| row
+                    .into_iter()
+                    .map(|x| if x == num { -1 } else { x })
+                    .collect()
+                )
+                .collect()
+            )
+            .collect();
+
+        let winning_boards: Vec<&Vec<Vec<i32>>> = boards.iter()
+            .filter(|board|
+                board.iter().filter(|row|
+                    row[0] == -1 && row[1] == -1 && row[2] == -1 && row[3] == -1 && row[4] == -1
+                ).collect::<Vec<&Vec<i32>>>().len() > 0 ||
+                [0, 1, 2, 3, 4].into_iter().filter(|column|
+                    board[0][*column] == -1 && board[1][*column] == -1 && board[2][*column] == -1 && board[3][*column] == -1 && board[4][*column] == -1
+                ).collect::<Vec<usize>>().len() > 0
+            ).collect();
+
+        if winning_boards.len() == boards.len() {
+            let sum: i32 = winning_boards.into_iter().last().into_iter().flatten().flatten().filter(|x| **x != -1).sum();
+            println!("Part 2, final score: {}", sum * num);
+            break;
+        }
+    }
+}