Submission #549734

#	Time	Username	Problem	Language	Result	Execution time	Memory
549734		Pherokung	The Kingdom of JOIOI (JOI17_joioi)	C++14	100 / 100	1642 ms	47472 KiB

joioi

#include<bits/stdc++.h>
using namespace std;
#define N 2005
#define F first
#define S second
int n,m,b[N][N],a[N][N],dp[N][N],ans=1e9;
typedef pair<int,int> pa;
 
bool cal(int n,int m,int v){
	for(int i=0;i<=n;i++) for(int j=0;j<=m;j++) dp[i][j] = 0;
	for(int i=0;i<=n;i++) dp[i][0] = 1;
	for(int i=0;i<=m;i++) dp[0][i] = 1;
	for(int i=1;i<=n;i++)for(int j=1;a[i][j] <=v && dp[i-1][j] && dp[i][j-1];j++) dp[i][j]=true;
	int mx0=0,mx1=0,mn0=1e9,mn1=1e9;
	for(int i=1;i<=n;i++) for(int j=1;j<=m;j++){
		if(!dp[i][j]) mx0 = max(mx0,a[i][j]), mn0 = min(mn0,a[i][j]);
		else mx1 = max(mx1,a[i][j]), mn1 = min(mn1,a[i][j]);
	}
	
	if(!dp[1][1]) return 0;
	if(dp[n][m]) return 1;
	ans = min(ans,max(mx1-mn1,mx0-mn0));
	if(mn1 >= mn0) return 0;
	return mx1-mn1 > mx0-mn0;
}
 
void sol(int n,int m){
	int be = 1,ed = 1e9;
	while(be < ed){
		int mid = (be+ed)/2;
		if(cal(n,m,mid)) ed = mid;
		else be = mid+1;
	}
}
 
int main(){
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) scanf("%d",&a[i][j]);
    sol(n,m);
    
    for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) b[i][j] = a[i][j];
    for(int i=1;i<=m;i++) for(int j=1;j<=n;j++) a[i][j] = b[n-j+1][i];
    sol(m,n);
    
	for(int i=1;i<=m;i++) for(int j=1;j<=n;j++) b[i][j] = a[i][j];
    for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) a[i][j] = b[m-j+1][i];
    sol(n,m);
    
	for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) b[i][j] = a[i][j];
    for(int i=1;i<=m;i++) for(int j=1;j<=n;j++) a[i][j] = b[n-j+1][i];
    sol(m,n);
 
	printf("%d",ans);
}

Compilation message (stderr)

joioi.cpp: In function 'int main()':
joioi.cpp:37:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |  scanf("%d%d",&n,&m);
      |  ~~~~~^~~~~~~~~~~~~~
joioi.cpp:38:51: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |  for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) scanf("%d",&a[i][j]);
      |                                              ~~~~~^~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 45 / 45
• Subtask 3: 40 / 40