题解 | 【模板】差分

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 5000005;
long long a[MAXN];
long long diff[MAXN];

//构建差分数组
void build_diff(int n){
    diff[1]=a[1];
    for(int i=2;i<=n;i++){
        diff[i]=a[i]-a[i-1];
    }
}

//修改
void change_diff(int l,int r,int d,int n){
    diff[l] += d;
    if(r+1<=n){
        diff[r+1] -= d;
    }
}

//还原
void restore(int n){
    a[1]=diff[1];
    for(int i=2;i<=n;i++){
        a[i] = a[i-1]+diff[i];
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n,q;
    cin>>n>>q;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    build_diff(n);
    while(q--){
        int l,r,d;
        cin>>l>>r>>d;
        
        change_diff(l,r,d,n);
        
        
    }
    restore(n);
    for(int i=1;i<=n;i++){
        cout<<a[i]<<" ";
    }
    return 0;
}