Submission #912567

#	Time	Username	Problem	Language	Result	Execution time	Memory
912567		penguin133	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	437 ms	180868 KiB

joioi

#include <bits/stdc++.h>
using namespace std;

//#define int long long
#define pi pair<int, int>
#define pii pair<int, pi>
#define fi first
#define se second
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

int n, m, A[2005][2005], P[2005][2005], S[2005][2005], P2[2005][2005], S2[2005][2005], P3[2005][2005], S3[2005][2005], P4[2005][2005], S4[2005][2005];

void solve(){
	cin >> n >> m;
	int mn = 1e18, mx = 0;
	for(int i=1;i<=n;i++){
		for(int j=1;j<=m;j++)cin >> A[i][j], mn = min(mn, A[i][j]), mx = max(mx, A[i][j]);
	}
	for(int i=1;i<=m;i++){
		P2[0][i] = S2[n + 1][i] = 1e18;
		for(int j=1;j<=n;j++){
			P[j][i] = max(P[j-1][i], A[j][i]);
			P2[j][i] = min(P2[j-1][i], A[j][i]);
		}
		for(int j=n;j>=1;j--){
			S[j][i] = max(S[j+1][i], A[j][i]);
			S2[j][i] = min(S2[j+1][i], A[j][i]);
		}
	}
	for(int i=1;i<=n;i++){
		P4[i][0] = S4[i][m+1] = 1e18;
		for(int j=1;j<=m;j++){
			P3[i][j] = max(P3[i][j-1], A[i][j]);
			P4[i][j] = min(P4[i][j-1], A[i][j]);
		}
		for(int j=m;j>=1;j--){
			S3[i][j] = max(S3[i][j+1], A[i][j]);
			S4[i][j] = min(S4[i][j+1], A[i][j]);
		}
	}
	int lo = 0, hi = (int)1e9, ans = hi;
	while(lo <= hi){
		int mid = (lo + hi) >> 1;
		int ptr = n, mn2 = 1e18;
		for(int i=1;i<=m;i++){
			while(ptr >= 1 && (P[ptr][i] > mn + mid || S2[ptr + 1][i] < mx - mid))ptr--;
			mn2 = min(mn2, S2[ptr + 1][i]);
		}
		bool f = (mn2 >= mx - mid);
		ptr = n, mn2 = 1e18;
		for(int i=m;i>=1;i--){
			while(ptr >= 1 && (P[ptr][i] > mn + mid || S2[ptr + 1][i] < mx - mid))ptr--;
			mn2 = min(mn2, S2[ptr + 1][i]);
		}
		f |= (mn2 >= mx - mid);
		int mx2 = 0;
		ptr = n;
		for(int i=1;i<=m;i++){
			while(ptr >= 1 && (P2[ptr][i] < mx - mid || S[ptr + 1][i] > mn + mid))ptr--;
			mx2 = max(mx2, S[ptr + 1][i]);
		}
		f |= (mx2 <= mn + mid);
		ptr = n, mx2 = 0;
		for(int i=m;i>=1;i--){
			while(ptr >= 1 && (P2[ptr][i] < mx - mid || S[ptr + 1][i] > mn + mid))ptr--;
			mx2 = max(mx2, S[ptr + 1][i]);
		}
		f |= (mx2 <= mn + mid);
		
		ptr = m, mn2 = 1e18;
		for(int i=1;i<=n;i++){
			while(ptr >= 1 && (P3[i][ptr] > mn + mid || S4[i][ptr + 1] < mx - mid))ptr--;
			mn2 = min(mn2, S4[i][ptr + 1]);
		}
		f |= (mn2 >= mx - mid);
		ptr = m, mn2 = 1e18;
		for(int i=n;i>=1;i--){
			while(ptr >= 1 && (P3[i][ptr] > mn + mid || S4[i][ptr + 1] < mx - mid))ptr--;
			mn2 = min(mn2, S4[i][ptr + 1]);
		}
		f |= (mn2 >= mx - mid);
		
		ptr = m, mx2 = 0;
		for(int i=1;i<=n;i++){
			while(ptr >= 1 && (P4[i][ptr] < mx - mid || S3[i][ptr + 1] > mn + mid))ptr--;
			mx2 = max(mx2, S3[i][ptr + 1]);
		}
		f |= (mx2 <= mn + mid);
		ptr = m, mx2 = 0;
		for(int i=n;i>=1;i--){
			while(ptr >= 1 && (P4[i][ptr] < mx - mid || S3[i][ptr + 1] > mn + mid))ptr--;
			mx2 = max(mx2, S3[i][ptr + 1]);
		}
		f |= (mx2 <= mn + mid);
		
		if(f)ans = mid, hi = mid - 1;
		else lo = mid + 1;
	}
	cout << ans;
}

main(){
	ios::sync_with_stdio(0);cin.tie(0);
	int tc = 1;
	//cin >> tc;
	for(int tc1=1;tc1<=tc;tc1++){
		// cout << "Case #" << tc1 << ": ";
		solve();
	}
}

Compilation message (stderr)

joioi.cpp: In function 'void solve()':
joioi.cpp:18:11: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
   18 |  int mn = 1e18, mx = 0;
      |           ^~~~
joioi.cpp:23:29: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
   23 |   P2[0][i] = S2[n + 1][i] = 1e18;
      |                             ^~~~
joioi.cpp:34:27: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
   34 |   P4[i][0] = S4[i][m+1] = 1e18;
      |                           ^~~~
joioi.cpp:47:22: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
   47 |   int ptr = n, mn2 = 1e18;
      |                      ^~~~
joioi.cpp:53:18: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
   53 |   ptr = n, mn2 = 1e18;
      |                  ^~~~
joioi.cpp:73:18: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
   73 |   ptr = m, mn2 = 1e18;
      |                  ^~~~
joioi.cpp:79:18: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
   79 |   ptr = m, mn2 = 1e18;
      |                  ^~~~
joioi.cpp: At global scope:
joioi.cpp:105:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  105 | main(){
      | ^~~~

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