Minimize the error
You are given two arrays A and B, each of size n. The error, E, between these two arrays is defined . You have to perform exactly k1 operations on array A and exactly k2 operations on array B. In one operation, you have to choose one element of the array and increase or decrease it by 1.
Output the minimum possible value of error after k1 operations on array A and k2 operations on array B have been performed.
Input
The first line contains three space-separated integers n (1 ≤ n ≤ 103), k1 and k2 (0 ≤ k1 + k2 ≤ 103, k1 and k2 are non-negative) — size of arrays and number of operations to perform on A and B respectively.
Second line contains n space separated integers a1, a2, ..., an ( - 106 ≤ ai ≤ 106) — array A.
Third line contains n space separated integers b1, b2, ..., bn ( - 106 ≤ bi ≤ 106)— array B.
OutputOutput a single integer — the minimum possible value of after doing exactly k1 operations on array A and exactly k2 operations on array B.
2 0 0 1 2 2 3
2
2 1 0 1 2 2 2
0
2 5 7 3 4 14 4
1
In the first sample case, we cannot perform any operations on A or B. Therefore the minimum possible error E = (1 - 2)2 + (2 - 3)2 = 2.
In the second sample case, we are required to perform exactly one operation on A. In order to minimize error, we increment the first element of A by 1. Now, A = [2, 2]. The error is now E = (2 - 2)2 + (2 - 2)2 = 0. This is the minimum possible error obtainable.
In the third sample case, we can increase the first element of A to 8, using the all of the 5 moves available to us. Also, the first element of B can be reduced to 8 using the 6 of the 7 available moves. Now A = [8, 4] and B = [8, 4]. The error is now E = (8 - 8)2 + (4 - 4)2 = 0, but we are still left with 1 move for array B. Increasing the second element of B to 5 using the left move, we get B = [8, 5] and E = (8 - 8)2 + (4 - 5)2 = 1.
思路:使用优先队列每次让差距的绝对值最大的减1,操作总次数是k1+k2,因为操作哪个数组无所谓,都是为了使差距减少1
注意使用longlong
code:
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>
using namespace std;
typedef long long ll;
int n,k1,k2;
struct node{
ll a,b;
ll dif;
bool operator < (const node &other)const{
return dif < other.dif;
}
}num[1100];
priority_queue<node> q;
int main(){
cin >> n >> k1 >> k2;
int sum = k1 + k2;
for(int i = 0; i < n; i++){
cin >> num[i].a;
}
for(int i = 0; i < n; i++){
cin >> num[i].b;
}
for(int i = 0; i < n; i++){
num[i].dif = abs(num[i].a - num[i].b);
q.push(num[i]);
}
while(sum--){
node tmp = q.top();
q.pop();
tmp.dif = abs(tmp.dif - 1ll);
q.push(tmp);
}
ll ans = 0;
while(!q.empty()){
node tmp = q.top();
q.pop();
ans += tmp.dif * tmp.dif;
}
cout << ans << endl;
return 0;
}
本文介绍了一个算法问题,即通过操作两个数组A和B来最小化它们之间的误差。具体操作为在给定的操作次数内,分别对两个数组进行元素增减以最小化最终的误差平方和。文章提供了一种解决方案,利用优先队列选择当前差距最大的元素进行操作。
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