#include <stdio.h> #include <stdlib.h> struct Segment { int left; int right; }; // 比较函数，排序用 int cmp(const void* a, const void* b) { struct Segment* seg1 = (struct Segment*)a; struct Segment* seg2 = (struct Segment*)b; if (seg1->left == seg2->left) { return seg1->right - seg2->right; } return seg1->left - seg2->left; } int main() { int n, m; scanf("%d%d", &n, &m); struct Segment* segments = (struct Segment*)malloc(n * sizeof(struct Segment)); for (int i = 0; i < n; i++) { scanf("%d%d", &(segments[i].left), &(segments[i].right)); } // 按照左端点排序，如果左端点相同，按照右端点从小到大排序 qsort(segments, n, sizeof(struct Segment), cmp); int ans = 0; int curRight = 0; int i = 0; while (i < n && curRight < m) { int maxRight = -1; int maxIndex = -1; while (i < n && segments[i].left <= curRight) { if (segments[i].right > maxRight) { maxRight = segments[i].right; maxIndex = i; } i++; } if (maxIndex == -1) { printf("wrong!\n"); return 0; } curRight = maxRight; ans++; } printf("the answer is %d\n", ans); free(segments); return 0; }修改一下代码使该代码可以多次输入

可以使用一个while循环来实现多次输入，每次输入前先清空上一次输入的segments数组。以下是修改后的代码：

#include <stdio.h> 
#include <stdlib.h>  

struct Segment {
    int left;
    int right;
};

// 比较函数，排序用 
int cmp(const void* a, const void* b) {
    struct Segment* seg1 = (struct Segment*)a;
    struct Segment* seg2 = (struct Segment*)b;
    if (seg1->left == seg2->left) {
        return seg1->right - seg2->right;
    }
    return seg1->left - seg2->left;
}

int main() {
    int n, m;
    while (scanf("%d%d", &n, &m) != EOF) {
        struct Segment* segments = (struct Segment*)malloc(n * sizeof(struct Segment));
        for (int i = 0; i < n; i++) {
            scanf("%d%d", &(segments[i].left), &(segments[i].right));
        }

        // 按照左端点排序，如果左端点相同，按照右端点从小到大排序 
        qsort(segments, n, sizeof(struct Segment), cmp);

        int ans = 0;
        int curRight = 0;
        int i = 0;
        while (i < n && curRight < m) {
            int maxRight = -1;
            int maxIndex = -1;
            while (i < n && segments[i].left <= curRight) {
                if (segments[i].right > maxRight) {
                    maxRight = segments[i].right;
                    maxIndex = i;
                }
                i++;
            }
            if (maxIndex == -1) {
                printf("wrong!\n");
                return 0;
            }
            curRight = maxRight;
            ans++;
        }

        printf("the answer is %d\n", ans);

        free(segments);
    }
    return 0;
}