Submission #1132313

#	Time	Username	Problem	Language	Result	Execution time	Memory
1132313		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>,pair<long long,long long>>> nodes;
	
	long long difference = 0;
	long long first = grid[0][0];
	long long iteration = 0;
	nodes.push({{0,0},{first,iteration}});
	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.first;
		long long citer = nodes.front().second.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];
				
			
				long long temp = difference;
				difference = max(difference,abs(newval - cval)); // tracks max difference in one kingdom 
				if (vals.find(newval) != vals.end()) {
					vals.erase(vals.find(newval));
				}

				if (difference > mid){
					
					vals.insert(newval);
					difference = temp;
					
				}
				//else if (difference == mid){
					//auto it = prev(vals.end());
					//auto it2 = vals.begin();
					//long long maxdiff = *it - *it2;
					//nodes.push({{nr,nc},{newval,citer + 1}});
					//return max(difference,maxdiff);
				//}
				else{
					vis[nr][nc] = true;
					nodes.push({{nr,nc},{min(newval,cval),citer + 1}});
				}
			}
			
		}
	}
	for(int i = 0;i<h;i++){
		
		bool x = true;
		for(int j = 0;j<w;j++){
			if (vis[i][0] == true && vis[i][w-1] == true && vis[i][j] == false && j != w-1){
				return 1e9;
			}
			if (vis[i][w-1] == false && vis[i][0] == false && vis[i][j] == true && j != 0){
				return 1e9;
			}
			
			if (vis[0][j] == true && vis[h-1][j] == true && vis[i][j] == false && i != h-1){
				return 1e9;
			}
			if (vis[h-1][j] == false && vis[0][j] == false && vis[i][j] == true && i != 0){
				return 1e9;
			}
		}
	}
				
	if (!vals.empty()) {
		auto it = prev(vals.end());
		auto it2 = vals.begin();
		long long maxdiff = *it - *it2;
		//cout << difference << ' ' << maxdiff << '\n';
		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