C++程式:檢查能否透過選擇盒子移除所有石頭
假設我們有一個包含N個元素的陣列A。考慮有N個盒子,它們呈圓形排列。第i個盒子包含A[i]塊石頭。我們必須檢查是否可以透過重複執行以下操作來移除所有石頭:選擇一個盒子,例如第i個盒子。對於範圍1到N中的每個j,從(i+j)個盒子中移除正好j塊石頭。(N+k)個盒子稱為第k個盒子。如果一個盒子沒有足夠的石頭,則無法執行此操作。
因此,如果輸入類似於A = [4, 5, 1, 2, 3],則輸出為True,因為我們可以從第二個盒子開始移除所有石頭。
為了解決這個問題,我們將遵循以下步驟:
n := size of A Define an array a of size (n + 1) Define an array b of size (n + 1) sum := 0, p := n * (n + 1) for initialize i := 1, when i <= n, update (increase i by 1), do: a[i] := A[i - 1] sum := sum + a[i] if sum mod p is not equal to 0, then: return false k := sum / p for initialize i := 1, when i <= n, update (increase i by 1), do: b[i] := a[i] - a[(i mod n) + 1] sum := 0 for initialize i := 1, when i <= n, update (increase i by 1), do: a[i] := b[i] sum := sum + a[i] if sum is not equal to 0, then: return false for initialize i := 1, when i <= n, update (increase i by 1), do: if (a[i] + k) mod n is not equal to 0 or a[i] + k < 0, then: return false return true
示例
讓我們看看下面的實現,以便更好地理解:
#include <bits/stdc++.h> using namespace std; bool solve(vector<int> A) { int n = A.size(); vector<int> a(n + 1); vector<int> b(n + 1); int sum = 0, p = n * (n + 1) / 2; for (int i = 1; i <= n; i++) { a[i] = A[i - 1]; sum += a[i]; } if (sum % p != 0) { return false; } int k = sum / p; for (int i = 1; i <= n; i++) { b[i] = a[i] - a[i % n + 1]; } sum = 0; for (int i = 1; i <= n; i++) { a[i] = b[i]; sum += a[i]; } if (sum != 0) { return false; } for (int i = 1; i <= n; i++) { if ((a[i] + k) % n != 0 || a[i] + k < 0) { return false; } } return true; } int main(){ vector<int> A = { 4, 5, 1, 2, 3 }; cout << solve(A) << endl; }
輸入
{ 4, 5, 1, 2, 3 }
輸出
1
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