Submission #729397

#	Time	Username	Problem	Language	Result	Execution time	Memory
729397		pcc	Dango Maker (JOI18_dango_maker)	C++14	33 / 100	840 ms	262144 KiB

dango_maker

#include <bits/stdc++.h>
using namespace std;
 
#define sh short
#define ll long long
#define pll pair<ll,ll>
#define fs first
#define sc second
#define _all(a) a.begin(),a.end()
#define pii pair<short,short>
 
const int mxn = 3030;
 
struct Edge{
	int to;
	short cap;
	Edge(){}
	Edge(int tt,short cc){
		to = tt,cap = cc;
	}
};
 
vector<Edge> edges;
vector<vector<int>> paths;
vector<int> level;
string s[mxn];
int st,ed;
 
void addedge(int a,int b){
	paths[a].push_back(edges.size());
	edges.push_back(Edge(b,1));
	paths[b].push_back(edges.size());
	edges.push_back(Edge(a,0));
}
 
bool bfs(){
	queue<int> q;
	fill(level.begin(),level.end(),-1);
	level[0] = 0;
	q.push(0);
	while(!q.empty()){
		auto now = q.front();
		q.pop();
		for(auto &id:paths[now]){
			if(!edges[id].cap)continue;
			auto nxt = edges[id].to;
			if(level[nxt] == -1){
				level[nxt] = level[now]+1;
				q.push(nxt);
			}
		}
	}
	return level[ed] != -1;
}
 
int dfs(int now,int lim){
	if(now == ed)return lim;
	int ans = 0;
	for(auto &id:paths[now]){
		if(!edges[id].cap)continue;
		if(!lim)break;
		auto nxt = edges[id].to;
		if(level[nxt] != level[now]+1)continue;
		auto re = dfs(nxt,min(edges[id].cap,(sh)lim));
		if(re == 0)continue;
		edges[id].cap -= re;
		edges[id^1].cap += re;
		ans += re;
		lim -= re;
	}
	return ans;
}
 
void solve(){
	int n,m;
	cin>>n>>m;
	for(int i =0 ;i<n;i++)cin>>s[i];
	vector<pii> right,down;
	for(int i = 0;i<n-2;i++){
		for(int j = 0;j<m;j++){
			if(s[i][j] == 'R'&&s[i+1][j] == 'G'&&s[i+2][j] == 'W')down.push_back({i,j});
		}
	}
	for(int i = 0;i<n;i++){
		for(int j = 0;j<m-2;j++){
			if(s[i].substr(j,3)=="RGW")right.push_back({i,j});
		}
	}
	sort(right.begin(),right.end());
	sort(down.begin(),down.end());
	paths = vector<vector<int>>(right.size()+down.size()+2);
	for(int i = 0;i<right.size();i++){
		pii tar = make_pair(right[i].fs-1,right[i].sc+1);
		auto p1 = lower_bound(_all(down),tar)-down.begin();
		if(p1 != down.size()&&down[p1].fs == right[i].fs-1&&down[p1].sc == right[i].sc+1)
			addedge(i+1,p1+right.size()+1);
		tar = make_pair(right[i].fs-2,right[i].sc+2);
		p1 = lower_bound(_all(down),tar)-down.begin();
		p1 = lower_bound(_all(down),tar)-down.begin();
		if(p1 != down.size()&&down[p1].fs == right[i].fs-2&&down[p1].sc == right[i].sc+2)
			addedge(i+1,p1+right.size()+1);
		p1 = lower_bound(_all(down),right[i])-down.begin();
		if(p1 != down.size()&&down[p1].fs == right[i].fs&&down[p1].sc == right[i].sc)
			addedge(i+1,p1+right.size()+1);
	}
	for(int i = 1;i<=right.size();i++)addedge(0,i);
	for(int i = right.size()+1;i<paths.size();i++)addedge(i,paths.size()-1);
	/*
	for(auto &i:down)cout<<i.fs<<' '<<i.sc<<',';cout<<endl;
	for(auto &i:right)cout<<i.fs<<' '<<i.sc<<',';cout<<endl;
	for(int i = 1;i<=right.size();i++){
		for(auto &id:paths[i]){
			if(edges[id].to == 0)continue;
			cout<<i<<','<<edges[id].to<<endl;
		}
	}
 
   */
	level = vector<int>(paths.size());
	int ans = 0;
	st = 0,ed = paths.size()-1;
	while(bfs()){
		int re;
		while(re = dfs(0,mxn*mxn))ans+= re;
	}
	cout<<right.size()+down.size()-ans;
	return;
}
 
int main(){
	ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	solve();
}

Compilation message (stderr)

dango_maker.cpp: In function 'void solve()':
dango_maker.cpp:92:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<short int, short int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   92 |  for(int i = 0;i<right.size();i++){
      |                ~^~~~~~~~~~~~~
dango_maker.cpp:95:9: warning: comparison of integer expressions of different signedness: 'long int' and 'std::vector<std::pair<short int, short int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   95 |   if(p1 != down.size()&&down[p1].fs == right[i].fs-1&&down[p1].sc == right[i].sc+1)
      |      ~~~^~~~~~~~~~~~~~
dango_maker.cpp:100:9: warning: comparison of integer expressions of different signedness: 'long int' and 'std::vector<std::pair<short int, short int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  100 |   if(p1 != down.size()&&down[p1].fs == right[i].fs-2&&down[p1].sc == right[i].sc+2)
      |      ~~~^~~~~~~~~~~~~~
dango_maker.cpp:103:9: warning: comparison of integer expressions of different signedness: 'long int' and 'std::vector<std::pair<short int, short int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  103 |   if(p1 != down.size()&&down[p1].fs == right[i].fs&&down[p1].sc == right[i].sc)
      |      ~~~^~~~~~~~~~~~~~
dango_maker.cpp:106:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<short int, short int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  106 |  for(int i = 1;i<=right.size();i++)addedge(0,i);
      |                ~^~~~~~~~~~~~~~
dango_maker.cpp:107:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  107 |  for(int i = right.size()+1;i<paths.size();i++)addedge(i,paths.size()-1);
      |                             ~^~~~~~~~~~~~~
dango_maker.cpp:124:12: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  124 |   while(re = dfs(0,mxn*mxn))ans+= re;
      |         ~~~^~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 20 / 20
• Subtask 3: 0 / 67