题解 | #游游的字母翻倍#

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int main() {
    int n, q;
    while (scanf("%d %d", &n, &q) != EOF) {
        char *str = (char*)malloc(sizeof(char) * (n + 1));
        if(str == NULL) {
            printf("内存分配失败");
            return 0;
        }
        scanf("%s",str);
        str[n] = '\0';
        int l, r;
        for(int i = 0; i < q; i++) {
            scanf("%d %d", &l, &r);
            int len = strlen(str);
            char* tmp = (char*)malloc(sizeof(char) * (len + r - l + 1));
            for(int j = 0; j < l - 1; j++) {
                tmp[j] = str[j];
            }
            int index = l - 1;
            for(int j = l - 1; j < r; j++) {
                tmp[index] = str[j];
                index++;
                tmp[index] = str[j];
                index++;
            }
            for(int j = r; j < len; j++) {
                tmp[index] = str[j];
                index++;
            }
            tmp[index] = '\0';
            str = tmp;
        }
        printf("%s\n",str);
    }
    return 0;
}