P3545 [POI2012]HUR-Warehouse Store [堆贪心]

$HUR-Warehouse\ \ Store$

题目描述见链接 .

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$\color{red}{正解部分}$

类似 这道题目, 都是使用堆进行 贪心 .

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$\color{red}{实现部分}$

#include<bits/stdc++.h>
#define reg register
typedef long long ll;
typedef std::pair<int,int> pr;

int read(){
        char c;
        int s = 0, flag = 1;
        while((c=getchar()) && !isdigit(c))
                if(c == '-'){ flag = -1, c = getchar(); break ; }
        while(isdigit(c)) s = s*10 + c-'0', c = getchar();
        return s * flag;
}

const int maxn = 1e6 + 5;

int N;
int Ans;
int A[maxn];
int B[maxn];

int main(){
        N = read();
        for(reg int i = 1; i <= N; i ++) A[i] = read();
        for(reg int i = 1; i <= N; i ++) B[i] = read();
        std::priority_queue <pr> Q;
        ll sum = 0;
        for(reg int i = 1; i <= N; i ++){
                sum += A[i];
                if(sum >= B[i]){
                        Q.push(pr(B[i], i));
                        sum -= B[i];
                        Ans ++;
                }else if(!Q.empty()){
                        int top = Q.top().second;
                        if(B[top] > B[i]){
                                Q.pop(), Q.push(pr(B[i], i));
                                sum += B[top] - B[i];
                        }
                }
        }
        printf("%d\n", Ans);
        int cnt = 0;
        while(!Q.empty()) A[++ cnt] = Q.top().second, Q.pop();
        std::sort(A+1, A+cnt+1);
        for(reg int i = 1; i <= cnt; i ++) printf("%d ", A[i]);
        return 0;
}