题解 | #DNA序列#

#include <stdio.h>
#include <string.h>

int main() {
    char str[1000];
    int n;
    scanf("%s",str);
    scanf("%d",&n);
    int len = strlen(str);
    float a[1000] = {0};
    for (int i = 0; i<len-n;i++) {
        float t = 0;
        for (int j = 0; j<n; j++) {
            if (str[i+j] == 'C' || str[i+j] == 'G') {
                t++;
            }
        }
        a[i] = t/n;
       // printf("%f\n",a[i]);
    }
    float max = 0;
    int c=0;
    for (int i = len-n-1; i>=0; i--) {//要找第一个	反过来循环就行
        max = (a[i]<max)?max:a[i];
        c = (a[i]<max)?c:i;
    }
    for (int i = 0; i<n; i++) {
        printf("%c",str[c+i]);
    }
       

    return 0;
}