56 lines
1.0 KiB
C
56 lines
1.0 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <limits.h>
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#define WINDOW_SIZE 3
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int main() {
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FILE *input = fopen("input", "r");
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if(input == NULL) {
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printf("oh noes couldn't open the input file lol\n");
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return 1;
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}
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char line[255];
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int index = 0, count = 0, last_num = INT_MAX;
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int windows[WINDOW_SIZE][WINDOW_SIZE];
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while(fgets(line, sizeof(line), input) != NULL) {
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int cur_num = atoi(line),
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cur_index = index % (WINDOW_SIZE);
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// Put values diagonal into the 3x3 grid, like this
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// A B C
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// B C A
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// C A B
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for(int i=0; i<WINDOW_SIZE; i++){
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int cur_col = (cur_index + i) % WINDOW_SIZE;
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windows[i][cur_col] = cur_num;
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}
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index++;
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if(index < WINDOW_SIZE) // skip first 3 values
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continue;
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// Calculate average for current column, e.g.
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// A B C
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// B C A
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// C A B
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// ^
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int sum = 0;
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for(int i=0; i<WINDOW_SIZE; i++)
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sum += windows[cur_index][i];
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count += sum > last_num;
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last_num = sum;
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}
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fclose(input);
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printf("There were %d measurements larger than the last.\n", count);
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}
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