42 lines
930 B
C++
42 lines
930 B
C++
#include <bits/stdc++.h>
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using namespace std;
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const int N = 1010;
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int a[N][N];
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int b[N][N];
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int n, m;
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/**
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* 功能：二维差分的模板
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* @param x1
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* @param y1
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* @param x2
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* @param y2
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* @param c
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*/
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void insert(int x1, int y1, int x2, int y2, int c) {
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b[x1][y1] += c;
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b[x2 + 1][y1] -= c;
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b[x1][y2 + 1] -= c;
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b[x2 + 1][y2 + 1] += c;
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}
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int main() {
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cin >> n >> m;
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while (m--) {
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int x1, y1, x2, y2;
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cin >> x1 >> y1 >> x2 >> y2;
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//对比二维差分的表示，四个加法运算，优化掉双重循环
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insert(x1, y1, x2, y2, 1);
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}
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//通过二维差分，还原成原始数组
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for (int i = 1; i <= n; i++) {
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for (int j = 1; j <= n; j++) {
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a[i][j] = a[i - 1][j] + a[i][j - 1] - a[i - 1][j - 1]+b[i][j];
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printf("%d ", a[i][j]);
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}
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printf("\n");
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}
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return 0;
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} |