C++程式碼:計算使兩個陣列相同所需的操作次數
假設我們有兩個包含n個元素的陣列A和B。考慮一個操作:選擇兩個索引i和j,然後將第i個元素減少1,並將第j個元素增加1。執行操作後,陣列的每個元素必須是非負的。我們想要使A和B相同。我們必須找到使A和B相同的操作序列。如果不可能,則返回-1。
因此,如果輸入類似於A = [1, 2, 3, 4];B = [3, 1, 2, 4],則輸出將為[(1, 0), (2, 0)],因為對於i = 1和j = 0,陣列將為[2, 1, 3, 4],然後對於i = 2和j = 0,它將為[3, 1, 2, 4]
步驟
為了解決這個問題,我們將遵循以下步驟:
a := 0, b := 0, c := 0 n := size of A Define an array C of size n and fill with 0 for initialize i := 0, when i < n, update (increase i by 1), do: a := a + A[i] for initialize i := 0, when i < n, update (increase i by 1), do: b := b + A[i] if a is not equal to b, then: return -1 Otherwise for initialize i := 0, when i < n, update (increase i by 1), do: c := c + |A[i] - B[i]| C[i] := A[i] - B[i] c := c / 2 i := 0 j := 0 while c is non-zero, decrease c after each iteration, do: while C[i] <= 0, do: (increase i by 1) while C[j] >= 0, do: (increase j by 1) print i and j decrease C[i] and increase C[j] by 1
示例
讓我們來看下面的實現以更好地理解:
#include <bits/stdc++.h>
using namespace std;
void solve(vector<int> A, vector<int> B){
int a = 0, b = 0, c = 0;
int n = A.size();
vector<int> C(n, 0);
for (int i = 0; i < n; i++)
a += A[i];
for (int i = 0; i < n; i++)
b += A[i];
if (a != b){
cout << -1;
return;
}
else{
for (int i = 0; i < n; i++){
c += abs(A[i] - B[i]);
C[i] = A[i] - B[i];
}
c = c / 2;
int i = 0, j = 0;
while (c--){
while (C[i] <= 0)
i++;
while (C[j] >= 0)
j++;
cout << "(" << i << ", " << j << "), ";
C[i]--, C[j]++;
}
}
}
int main(){
vector<int> A = { 1, 2, 3, 4 };
vector<int> B = { 3, 1, 2, 4 };
solve(A, B);
}輸入
{ 1, 2, 3, 4 }, { 3, 1, 2, 4 }輸出
(1, 0), (2, 0),
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