Submission #332875

#	Time	Username	Problem	Language	Result	Execution time	Memory
332875		limabeans	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	3793 ms	102764 KiB

joioi

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

template<typename T>
void out(T x) { cout << x << endl; exit(0); }
#define watch(x) cout << (#x) << " is " << (x) << endl





using ll = long long;

const ll inf = 1e18;
const int maxn = 2020;


int n,m;
ll g[maxn][maxn];
ll tmp[maxn][maxn];

ll mn = inf;
ll mx = -inf;

bool test(ll diff) {
    {
	int sep = 0;
	bool ok = true;
	for (int i=0; i<n; i++) {
	    for (int j=0; j<m; j++) {
		if (g[i][j]<mx-diff) {
		    sep = max(sep,j+1);
		}
	    }
	    for (int j=0; j<m; j++) {
		if (g[i][j]>mn+diff) {
		    if (j<sep) ok = false;
		}
	    }
	}
	if (ok) return true;
    }

    {
	int sep = 0;
	bool ok = true;
	for (int i=0; i<n; i++) {
	    for (int j=0; j<m; j++) {
		if (g[i][j]>mn+diff) {
		    sep = max(sep,j+1);
		}
	    }
	    for (int j=0; j<m; j++) {
		if (g[i][j]<mx-diff) {
		    if (j<sep) ok = false;
		}
	    }
	}
	if (ok) return true;
    }

    return false;
}

ll solve() {

    ll diff = mx-mn;
    ll hi = diff;
    ll lo = -1;
    while (hi-lo>1) {
	ll mid = (lo+hi)/2;
	if (test(mid)) {
	    hi = mid;
	} else {
	    lo = mid;
	}
    }
    

    return hi;
}


void flipY() {
    for (int i=0; i<n; i++) {
	for (int j=0; j<m/2; j++) {
	    swap(g[i][j],g[i][m-j-1]);
	}
    }
}

void transpose() {
    for (int i=0; i<n; i++) {
	for (int j=0; j<m; j++) {
	    tmp[j][i]=g[i][j];
	}
    }
    swap(n,m);
    for (int i=0; i<n; i++) {
	for (int j=0; j<m; j++) {
	    g[i][j]=tmp[i][j];
	}
    }
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(0);  cout.tie(0);


    cin>>n>>m;
    for (int i=0; i<n; i++) {
	for (int j=0; j<m; j++) {
	    cin>>g[i][j];
	}
    }

    for (int i=0; i<n; i++) {
	for (int j=0; j<m; j++) {
	    mn = min(mn, g[i][j]);
	    mx = max(mx, g[i][j]);
	}
    }

    ll res = inf;
    res = min(res, solve());
    flipY();
    res = min(res, solve());
    flipY(); transpose();
    res = min(res, solve());
    flipY();
    res = min(res, solve());

    cout<<res<<endl;
    
    return 0;
}

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