题解 | 活动安排

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

struct st{
    long long a;
    long long b;
};

int com(const void *a,const void *b)
{
    struct st * aa = (struct st *)a;
    struct st * bb = (struct st *)b;
    return aa->b - bb->b;
}

int main() {
    int i,j=0, n, tmp, num=0, t=1;
    scanf("%d",&n);
    struct st *nu = (struct st *)malloc(sizeof(struct st) * n);
    
    for(int i=0;i<n;i++)
    {
        scanf("%lld %lld",&nu[i].a,&nu[i].b);
    }
    qsort(nu, n, sizeof(struct st), com);
    i=0;
    while(i<n-1)
    {
        j=i+1;
        while(nu[j].a < nu[i].b && j<n)
        {
            j++;
        }
        if(j<n)
        {
            t++;
            i=j;
        }
        else {
            break;
        }

    }
    printf("%d\n",t);
    return 0;
}