Submission #153537

#	Time	Username	Problem	Language	Result	Execution time	Memory
153537		mhy908	Dango Maker (JOI18_dango_maker)	C++14	33 / 100	1242 ms	262144 KiB

dango_maker

#include <bits/stdc++.h>
#define pb push_back
#define INF 987654321
using namespace std;
typedef long long LL;
int n, m, x;
vector<char> str[3010];
int col[3010][3010][2], ans;
short re[3010][3010];
vector<int> link[3000001], id;
vector<int> par;
vector<bool> used;
vector<int> dist, A, B;
vector<vector<int> > vc;
map<int, int> mp;
queue<int> Q;
int findpar(int num)
{
    if(num==par[num])return num;
    return par[num]=findpar(par[num]);
}
void mergepar(int a, int b)
{
    a=findpar(a);
    b=findpar(b);
    par[a]=par[b];
}
void bfs(int p)
{
    for(int i=0; i<vc[p].size(); i++){
        if(!used[i]){
            dist[i]=0;
            Q.push(i);
        }
        else dist[i]=INF;
    }
    while(!Q.empty()){
        int a=Q.front();
        Q.pop();
        for(int b: link[vc[p][a]]){
            b=mp[b];
            if(B[b]!=-1&&dist[B[b]]==INF){
                dist[B[b]]=dist[a]+1;
                Q.push(B[b]);
            }
        }
    }
}
bool dfs(int p, int a){
    for(int b: link[vc[p][a]]){
        b=mp[b];
        if(B[b]==-1||dist[B[b]]==dist[a]+1&&dfs(p, B[b])){
            used[a]=true;
            A[a]=b;
            B[b]=a;
            return true;
        }
    }
    return false;
}
int hopcroft_carp(int p)
{
    int match=0;
    while(1){
        bfs(p);
        int flow=0;
        for(int i=0; i<vc[p].size(); i++)
            if(!used[i]&&dfs(p, i))flow++;
        if(!flow)break;
        match+=flow;
    }
    return match/2;
}
int main()
{
    scanf("%d%d", &n, &m);
    for(int i=1; i<=n; i++){
        str[i].pb(0);
        for(int j=1; j<=m; j++){
            char y;
            scanf(" %c", &y);
            str[i].pb(y);
        }
    }
    for(int i=1; i<=n; i++){
        for(int j=1; j<=m; j++){
            if(j+2<=m)
                if(str[i][j]=='R'&&str[i][j+1]=='G'&&str[i][j+2]=='W'){
                    ++x;
                    col[i][j][re[i][j]++]=x;
                    col[i][j+1][re[i][j+1]++]=x;
                    col[i][j+2][re[i][j+2]++]=x;
                }
            if(i+2<=n)
                if(str[i][j]=='R'&&str[i+1][j]=='G'&&str[i+2][j]=='W'){
                    ++x;
                    col[i][j][re[i][j]++]=x;
                    col[i+1][j][re[i+1][j]++]=x;
                    col[i+2][j][re[i+2][j]++]=x;
                }
        }
    }
    for(int i=1; i<=n; i++){
        str[i].clear();
        vector<char>().swap(str[i]);
    }
    for(int i=0; i<=x; i++)par.pb(i);
    for(int i=1; i<=n; i++){
        for(int j=1; j<=m; j++){
            if(re[i][j]==2){
                mergepar(col[i][j][1], col[i][j][0]);
                link[col[i][j][1]].pb(col[i][j][0]);
                link[col[i][j][0]].pb(col[i][j][1]);
            }
        }
    }
    for(int i=1; i<=x; i++){
        id.pb(findpar(i));
    }
    sort(id.begin(), id.end());
    id.erase(unique(id.begin(), id.end()), id.end());
    int maxpar=1;
    for(int i=1; i<=x; i++){
        par[i]=lower_bound(id.begin(), id.end(), par[i])-id.begin();
        maxpar=max(maxpar, par[i]+1);
    }
    id.clear();
    vector<int>().swap(id);
    vc.resize(maxpar);
    for(int i=1; i<=x; i++){
        vc[par[i]].pb(i);
    }
    par.clear();
    vector<int>().swap(par);
    for(int i=0; i<maxpar; i++){
        if(vc[i].size()==1)ans++;
        else{
            for(int j=0; j<vc[i].size(); j++)mp[vc[i][j]]=j;
            used.resize(vc[i].size()+2, false);
            dist.resize(vc[i].size()+2, 0);
            A.resize(vc[i].size()+2, -1);
            B.resize(vc[i].size()+2, -1);
            ans+=vc[i].size()-hopcroft_carp(i);
            mp.clear();
            dist.clear();
            A.clear();
            B.clear();
            used.clear();
            vector<int>().swap(dist);
            vector<int>().swap(A);
            vector<int>().swap(B);
            vector<bool>().swap(used);
        }
    }
    printf("%d", ans);
}

Compilation message (stderr)

dango_maker.cpp: In function 'void bfs(int)':
dango_maker.cpp:30:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<vc[p].size(); i++){
                  ~^~~~~~~~~~~~~
dango_maker.cpp: In function 'bool dfs(int, int)':
dango_maker.cpp:52:43: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
         if(B[b]==-1||dist[B[b]]==dist[a]+1&&dfs(p, B[b])){
dango_maker.cpp: In function 'int hopcroft_carp(int)':
dango_maker.cpp:67:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0; i<vc[p].size(); i++)
                      ~^~~~~~~~~~~~~
dango_maker.cpp: In function 'int main()':
dango_maker.cpp:138:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int j=0; j<vc[i].size(); j++)mp[vc[i][j]]=j;
                          ~^~~~~~~~~~~~~
dango_maker.cpp:76:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~
dango_maker.cpp:81:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf(" %c", &y);
             ~~~~~^~~~~~~~~~~

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