事件序列问题 贪心法

/* 事件序列问题 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <algorithm>

using namespace std;
typedef struct event {
    int no, bgn, en;
} event_t;

bool cmp(const event_t e1, const event_t e2) {
    return e1.en < e2.en;
}

const int N = 12;
event_t arr[N];
int res[N];

int main() {
    FILE * fin = fopen("in.txt", "r");
    for (int i = 0; i < 12; i++) {
        arr[i].no = i;
        fscanf(fin, "%d %d", &arr[i].bgn, &arr[i].en);
    }
    sort(arr, arr + N, cmp);
    int i = 0, index = 0, startTime = 0;
    while (i < N) {
        if (arr[i].bgn >= startTime) {
            res[index++] = arr[i].no;
            startTime = arr[i].en;
        }
        i++;
    }
    for (int j = 0; j < index; j++)
        printf("%d ", res[j]);
    putchar('\n');
    fclose(fin);
    return 0;
}
/*
1 3
3 4
0 7
3 8
2 9
5 10
6 12
4 14
10 15
8 18
15 19
15 20
*/