题解 | 小红的优惠券

#include <stdio.h>

int main(void) {
    int n, m;
    scanf("%d%d", &n, &m);

    int a[100005], b[100005];
    for(int j = 0; j < m; j++)
        scanf("%d%d", &a[j], &b[j]);
    
    int min = n;
    int actual_n = n;
    for(int i = 0; i < m; i++){
        if(n >= a[i])
            actual_n = n - b[i];
        if(actual_n < min)
            min = actual_n;
        
        actual_n = n;
    }
    printf("%d\n", min);

    return 0;
}