Submission #1132304

#	Time	Username	Problem	Language	Result	Execution time	Memory
1132304		henriess	The Kingdom of JOIOI (JOI17_joioi)	C++20	0 / 100	0 ms	320 KiB

joioi

#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;


vector<vector<long long>> grid;
vector<pair<long long,long long>> moves = {{0,-1},{0,1},{-1,0},{1,0}};


long long h,w;
multiset<long long> ogvals;
long long bfs(long long mid){
	multiset<long long> vals = ogvals;
	queue<pair<pair<long long,long long>,long long>> nodes;
	
	long long difference = 0;
	long long first = grid[0][0];

	nodes.push({{0,0},first});
	vals.erase(first);
	vector<vector<bool>> vis;
	vis.resize(h,vector<bool>(w,false));
	vis[0][0] = true;
	while (!nodes.empty()){
		long long cr = nodes.front().first.first;
		long long cc = nodes.front().first.second;
		long long cval = nodes.front().second;
		nodes.pop();
		for(auto move : moves){
			long long nr = cr + move.first;
			long long nc = cc + move.second;
			if (nr >= 0 && nr < h && nc >= 0 && nc < w && vis[nr][nc] != true){
				long long newval = grid[nr][nc];
				nodes.push({{nr,nc},newval});
				vis[nr][nc] = true;
				long long temp = difference;
				difference = max(difference,newval - cval); // tracks max difference in one kingdom 
				vals.erase(vals.find(newval));
				if (difference > mid){
					vals.insert(newval);
					difference = temp;
					auto it = prev(vals.end());
					auto it2 = vals.begin();
					long long maxdiff = *it - *it2;
					return max(difference,maxdiff);
				}
				else if (difference == mid){
					auto it = prev(vals.end());
					auto it2 = vals.begin();
					long long maxdiff = *it - *it2;
					return max(difference,maxdiff);
				}
				
			}
			
		}
	}
	return difference;
}

bool check(long long mid){
	
	long long r = bfs(mid);
	return r <= mid;
}
void bsearch(){
	long long lb = 0;
	long long ub = 1e9;
	long long mid = -1;
	long long res = -1;
	while (lb <= ub){
		mid = (lb + ub) / 2;
		if (check(mid)){
			res = mid;
			ub = mid - 1;
		}
		else{
			lb = mid + 1;
		}
	}
	cout << res;
}
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
	
	cin >> h >> w;
	grid.resize(h,vector<long long>(w));

	
	for(int i = 0;i<h;i++){
		for(int j = 0;j<w;j++){
			long long alt;cin >> alt;
			grid[i][j] = alt;
			ogvals.insert(alt);
		}
	}
	
	bsearch();
}

• Subtask 1: 0 / 15
• Subtask 2: 0 / 45
• Subtask 3: 0 / 40