题解 | #DNA序列#

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int isGC(char a) {
    if(a == 'G' || a == 'C') return 1;
    return 0;
}

int main() {
    char input[1001];
    int n;
    while (scanf("%s\n%d", input, &n) != EOF) {
        int len = strlen(input);
        int substrnum = len - n;
        float *ratio = (float *)malloc((substrnum) * sizeof(float));
        int maxratioindex = 0;
        for(int i = 0; i < substrnum; i++) {
            ratio[i] = 0;
            for(int j = 0; j < n; j++) {
                ratio[i] += isGC(input[i + j]);
            }
            ratio[i] /= n;
            if(ratio[i] > ratio[maxratioindex]) {
                maxratioindex = i;
            }
        }
        for(int i = maxratioindex; i < maxratioindex + n; i++) {
            printf("%c", input[i]);
        }
    }
    return 0;
}