题目

差分

算法核心

差分数组b[]，需要记住的是b[]就相当于是一个增量。

• 边界：a[0] = b[0]
• 普适公式：b[i] = a[i] - a[i - 1]或者是a[i] = a[i - 1] + b[i]。

代码

#include <iostream>

using namespace std;

const int N = 1e5 + 10;

int n, m;
int a[N], b[N];
int l, r, c;

int main()
{
    cin >> n >> m;
    for (int i = 0; i < n; i ++ ) cin >> a[i];
    b[0] = a[0];
    for (int i = 1; i < n; i ++ )
        b[i] = a[i] - a[i - 1];
    
    while (m --)
    {
        cin >> l >> r >> c;
        b[l - 1] += c;
        b[r] -= c;
    }
    
    a[0] = b[0];
    for (int i = 1; i < n; i ++ )
        a[i] = a[i - 1] + b[i];
    
    for (int i = 0; i < n; i ++ )
        cout << a[i] << ' ';
    cout << endl;
    
    return 0;
}