184. go 实现大顶堆操作(力扣502. IPO)

package main

import (
	"container/heap"
	"sort"
)

func findMaximizedCapital(k, w int, profits, capital []int) int {
	n := len(profits)
	type pair struct {
		c, p int
	}
	arr := make([]pair, n) // 开辟空间
	for i, p := range profits {
		arr[i] = pair{capital[i], p}
	}
	sort.Slice(arr, func(i, j int) bool {
		return arr[i].c < arr[j].c
	})

	h := &hp{}
	for cur := 0; k > 0; k-- {
		for cur < n && arr[cur].c <= w {
			heap.Push(h, arr[cur].p)
			cur++
		}
		if len(h.IntSlice) > 0 {
			w += heap.Pop(h).(int)
		} else {
			break
		}
	}
	return w
}

type hp struct{ sort.IntSlice }

//https://pkg.go.dev/container/heap
// 实现Less方法, 因为要通过小于方法实现大顶堆,所以需要进行反向判断,将小于改成大于
func (this hp) Less(i, j int) bool {
	return this.IntSlice[i] > this.IntSlice[j]
}

// 实现Push方法, 跟着官网做就好了
func (this *hp) Push(v interface{}) {
	this.IntSlice = append(this.IntSlice, v.(int))
}

// 神奇的操作
func (this *hp) Pop() interface{} {
	a := this.IntSlice
	v := a[len(a)-1]
	this.IntSlice = a[:len(a)-1]
	return v
}