二维前缀和模板:
预处理:dp[i][j]=dp[i-1][j]+dp[i][j-1]-dp[i-1][j-1]+map[i][j];
查询:dp[x2][y2]+dp[x1-1][y1-1]-dp[x1-1][y2]-dp[x2][y1-1]
三维前缀和模板:
预处理:
pre[i][j][k]=mp[i][j][k]-pre[i-1][j-1][k]-pre[i-1][j][k-1]-pre[i][j-1][k-1]+pre[i][j][k-1]+pre[i][j-1][k]+pre[i-1][j][k]+pre[i-1][j-1][k-1];
查询:
res=pre[x2][y2][z2]-pre[x1][y2][z2]-pre[x2][y1][z2]-pre[x2][y2][z1]+pre[x1][y1][z2]+pre[x1][y2][z1]+pre[x2][y1][z1]-pre[x1][y1][z1];
三维前缀和模板题:
https://atcoder.jp/contests/abc366/tasks/abc366_d
#include<bits/stdc++.h>
#define endl '\n'
#define int long long
#define lowbit(x) (x&-x)
using namespace std;
const double pi=acos(-1);
void solve(){
int n;cin>>n;
vector<vector<vector<int>>> mp(n+1,vector<vector<int>>(n+1,vector<int>(n+1,0ll)));
vector<vector<vector<int>>> pre(n+1,vector<vector<int>>(n+1,vector<int>(n+1,0ll)));
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
for(int k=1;k<=n;k++){
cin>>mp[i][j][k];
}
}
}
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
for(int k=1;k<=n;k++){
pre[i][j][k]=mp[i][j][k]-pre[i-1][j-1][k]-pre[i-1][j][k-1]-pre[i][j-1][k-1]+pre[i][j][k-1]+pre[i][j-1][k]+pre[i-1][j][k]+pre[i-1][j-1][k-1];
}
}
}
int q;cin>>q;
while(q--){
int x1,x2,y1,y2,z1,z2;cin>>x1>>x2>>y1>>y2>>z1>>z2;
x1--,y1--,z1--;
int res=0;
res=pre[x2][y2][z2]-pre[x1][y2][z2]-pre[x2][y1][z2]-pre[x2][y2][z1]+pre[x1][y1][z2]+pre[x1][y2][z1]+pre[x2][y1][z1]-pre[x1][y1][z1];
cout<<res<<endl;
}
}
signed main(){
ios::sync_with_stdio(false); cin.tie(nullptr);
int t=1;
//cin>>t;
while(t--) solve();
return 0;
}
标签:pre,y2,前缀,三维,x2,y1,x1,z1
From: https://www.cnblogs.com/TaopiTTT/p/18466223