Monitor
http://codeforces.com/contest/846/problem/D
題解:二維RMQ問題+ST表
/* *@Author: STZG *@Language: C++ */ #include <bits/stdc++.h> #include<iostream> #include<algorithm> #include<cstdlib> #include<cstring> #include<cstdio> #include<string> #include<vector> #include<bitset> #include<queue> #include<deque> #include<stack> #include<cmath> #include<list> #include<map> #include<set> //#define DEBUG #define RI register int #define endl "\n" using namespace std; typedef long long ll; //typedef __int128 lll; const int N=500+10; const int M=100000+10; const int MOD=1e9+7; const double PI = acos(-1.0); const double EXP = 1E-8; const int INF = 0x3f3f3f3f; int t,n,m,k,q,l,r,u,v,x,y; int ans,cnt,flag,temp,sum; int a[N][N]; int dp[N][N]; int c[N][N]; char str; struct node{}; void ST(int x){for(int i=1;i<=m;i++){dp[i][0]=a[x][i];}for(int j=0;(1<<j)<m;j++){for(int i=1;i+(1<<j)<=m;i++){dp[i][j+1]=max(dp[i][j],dp[i+(1<<j)][j]);}}for(int i=1;i<=m-k+1;i++)c[x][i]=max(dp[i][t],dp[i+k-(1<<t)][t]); } void ST2(int x){for(int i=1;i<=n;i++){dp[i][0]=c[i][x];}for(int j=0;(1<<j)<n;j++){for(int i=1;i+(1<<j)<=n;i++){dp[i][j+1]=max(dp[i][j],dp[i+(1<<j)][j]);}}for(int i=1;i<=n-k+1;i++)ans=min(ans,max(dp[i][t],dp[i+k-(1<<t)][t]));} int main() { #ifdef DEBUGfreopen("input.in", "r", stdin);//freopen("output.out", "w", stdout); #endif//ios::sync_with_stdio(false);//cin.tie(0);//cout.tie(0);//scanf("%d",&t);//while(t--){scanf("%d%d%d%d",&n,&m,&k,&q);memset(a,INF,sizeof(a));while(q--){scanf("%d%d%d",&x,&y,&t);a[x][y]=t;}t=log2(k);for(int i=1;i<=n;i++)ST(i);ans=INF;for(int i=1;i<=m-k+1;i++)ST2(i);cout<<(ans==INF?-1:ans)<<endl;//}#ifdef DEBUGprintf("Time cost : %lf s\n",(double)clock()/CLOCKS_PER_SEC); #endif//cout << "Hello world!" << endl;return 0; }?
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