题解 | 小红的优惠券

package main

import (
    "fmt"
)

func main() {
    n, m := 0, 0
    fmt.Scan(&n)
    fmt.Scan(&m)
    coupon := make(map[int]int)
    aj, bj := 0, 0
    for i := 0; i < m; i++ {
        fmt.Scan(&aj, &bj)
        coupon[aj] = bj
    }
    // fmt.Println(n, m, coupon)
    var min int = n
    for k, v := range coupon {
        if n - k >= 0 {
            // 结算金额大于优惠券门槛
            min = minNum(n-v, min)
        }
    }
    fmt.Print(min)
}

func minNum(a, b int) int {
    if a < b {
        return a
    } else {
        return b
    }
}