Submission #581912

# Submission time Handle Problem Language Result Execution time Memory
581912 2022-06-23T08:01:31 Z 조영욱(#8367) 전압 (JOI14_voltage) C++14
45 / 100
191 ms 17500 KB
#include <bits/stdc++.h>
using namespace std;

typedef pair<int,int> P;
vector<P> edge;
vector<int> adj[100001];
int n,m;
int p[100001];

int find(int a) {
    return p[a]<0?a:p[a]=find(p[a]);
}

void merge(int a,int b) {
    a=find(a);
    b=find(b);
    if (a==b){
        return;
    }
    p[b]=a;
}

int dep[100001];
int par[100001];
vector<int> vec;
int root[100001];

void dfs(int v,int prev){
    par[v]=prev;
    for(int i=0;i<adj[v].size();i++) {
        int nt=adj[v][i];
        root[nt]=root[v];
        if (nt!=prev) {
            dep[nt]=dep[v]+1;
            dfs(nt,v);
        }
    }
}

int ind[100001];
int mn[100001];
bool vis[100001];
int f=1;

void dfs1(int v,int prev) {
    vis[v]=true;
    ind[v]=f++;
    mn[v]=ind[v];
    int cnt=0;
    for(int i=0;i<adj[v].size();i++) {
        int nt=adj[v][i];
        if (vis[nt]) {
            if (nt==prev) {
                cnt++;
            }
            if (nt!=prev||cnt>1)
                mn[v]=min(mn[v],ind[nt]);
            continue;
        }
        dfs1(nt,v);
        mn[v]=min(mn[v],mn[nt]);
    }
}

int value[100001];

void dfs2(int v,int type) {
    vis[v]=true;
    value[v]=type;
    for(int i=0;i<adj[v].size();i++) {
        int nt=adj[v][i];
        if (!vis[nt])
            dfs2(nt,-type);
    }
}

int pl[100002];
int temp[100002];

int main(void){
    scanf("%d %d",&n,&m);
    for(int i=0;i<m;i++) {
        int u,v;
        scanf("%d %d",&u,&v);
        edge.push_back(P(u,v));
        assert(u!=v);
    }
    memset(p,-1,sizeof(p));
    for(int i=0;i<m;i++) {
        if (find(edge[i].first)!=find(edge[i].second)) {
            adj[edge[i].first].push_back(edge[i].second);
            adj[edge[i].second].push_back(edge[i].first);
            merge(edge[i].first,edge[i].second);
        }
    }
    for(int i=1;i<=n;i++) {
        if (dep[i]==0) {
            root[i]=i;
            dfs(i,0);
        }
    }
    for(int i=1;i<=n;i++) {
        adj[i].clear();
    }
    bool flag=false;
    int d=0;
    int pr=-1;
    for(int i=0;i<m;i++) {
        adj[edge[i].first].push_back(edge[i].second);
        adj[edge[i].second].push_back(edge[i].first);
        if (dep[edge[i].first]%2==dep[edge[i].second]%2) {
            if (flag) {
                if (root[edge[i].first]!=pr) {
                    printf("0");
                }
                continue;
            }
            pr=root[edge[i].first];
            flag=true;
            int lca=-1;
            int a=edge[i].first;
            int b=edge[i].second;
            if (dep[a]<dep[b]) {
                swap(a,b);
            }
            while (dep[a]>dep[b]) {
                a=par[a];
                d++;
            }
            while (a!=b) {
                a=par[a];
                b=par[b];
                d+=2;
            }
            d++;
            lca=a;
            P save=edge[i];
            while (edge[i].first!=lca) {
                vec.push_back(edge[i].first);
                edge[i].first=par[edge[i].first];
            }
            vec.push_back(lca);
            vector<int> temp;
            while (edge[i].second!=lca) {
                temp.push_back(edge[i].second);
                edge[i].second=par[edge[i].second];
            }
            edge[i]=save;
            reverse(temp.begin(),temp.end());
            for(int j=0;j<temp.size();j++) {
                vec.push_back(temp[j]);
            }
        }
    }
    if (!flag) {
        int ret=0;
        for(int i=1;i<=n;i++) {
            if (!vis[i]) {
                dfs1(i,0);
                ret--;
                assert(ind[i]==mn[i]);
            }
        }
        for(int i=1;i<=n;i++) {
            if (ind[i]==mn[i]) {
                ret++;
            }
        }
        printf("%d",ret);
        return 0;
    }
    for(int i=0;i<d;i++) {
        vis[vec[i]]=true;
    }
    for(int i=0;i<d;i++) {
        dfs2(vec[i],i+1);
    }
    for(int i=0;i<m;i++) {
        if (value[edge[i].first]==value[edge[i].second]) {
            printf("0");
            return 0;
        }
        int one=value[edge[i].first];
        int two=value[edge[i].second];
        if (one>0&&two>0&&one<=d&&two<=d&&vec[one-1]==edge[i].first&&vec[two-1]==edge[i].second&&(one+1==two||two+1==one||two-one==d-1||one-two==d-1)) {
            int small;
            if (abs(one-two)!=1) {
                small=d;
            }
            else {
                small=min(one,two);
            }
            temp[small]++;
            if (temp[small]>1) {
                pl[small]++;
                pl[small+1]--;
            }
            continue;
        }
        if (one+two==0) {
            continue;
        }
        if (one<0&&two>0) {
            swap(one,two);
        }
        if (1LL*one*two>0) {
            one=abs(one);
            two=abs(two);
            bool flag=false;
            if (two>one&&(two-one)%2==1) {
                flag=true;
            }
            if (two<one&&(two-one)%2==0) {
                flag=true;
            }
            if (flag) {
                swap(one,two);
            }
            if (one<two) {
                pl[1]++;
                pl[one+1]--;
                pl[two+1]++;
                pl[d+1]--;
            }
            else {
                pl[two+1]++;
                pl[one+1]--;
            }
        }
        else {
            one=abs(one);
            two=abs(two);
            one=abs(one);
            two=abs(two);
            bool flag=false;
            if (two>one&&(two-one)%2==1) {
                flag=true;
            }
            if (two<one&&(two-one)%2==0) {
                flag=true;
            }
            if (!flag) {
                swap(one,two);
            }
            if (one<two) {
                pl[1]++;
                pl[one+1]--;
                pl[two+1]++;
                pl[d+1]--;
            }
            else {
                pl[two+1]++;
                pl[one+1]--;
            }
        }
    }
    int ret=0;
    int val=0;
    for(int i=1;i<=d;i++) {
        val+=pl[i];
        if (val==0) {
            ret++;
        }
    }
    printf("%d",ret);
}

Compilation message

voltage.cpp: In function 'void dfs(int, int)':
voltage.cpp:30:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |     for(int i=0;i<adj[v].size();i++) {
      |                 ~^~~~~~~~~~~~~~
voltage.cpp: In function 'void dfs1(int, int)':
voltage.cpp:50:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |     for(int i=0;i<adj[v].size();i++) {
      |                 ~^~~~~~~~~~~~~~
voltage.cpp: In function 'void dfs2(int, int)':
voltage.cpp:70:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   70 |     for(int i=0;i<adj[v].size();i++) {
      |                 ~^~~~~~~~~~~~~~
voltage.cpp: In function 'int main()':
voltage.cpp:150:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  150 |             for(int j=0;j<temp.size();j++) {
      |                         ~^~~~~~~~~~~~
voltage.cpp:81:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   81 |     scanf("%d %d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~~
voltage.cpp:84:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |         scanf("%d %d",&u,&v);
      |         ~~~~~^~~~~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Correct 2 ms 3156 KB Output is correct
2 Correct 3 ms 3028 KB Output is correct
3 Correct 3 ms 3028 KB Output is correct
4 Correct 2 ms 3028 KB Output is correct
5 Correct 3 ms 3156 KB Output is correct
6 Correct 3 ms 3156 KB Output is correct
7 Correct 2 ms 3156 KB Output is correct
8 Incorrect 3 ms 3052 KB Output isn't correct
9 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 51 ms 9396 KB Output is correct
2 Correct 98 ms 13436 KB Output is correct
3 Correct 48 ms 9020 KB Output is correct
4 Correct 87 ms 13528 KB Output is correct
5 Correct 7 ms 3924 KB Output is correct
6 Correct 109 ms 11492 KB Output is correct
7 Correct 87 ms 13656 KB Output is correct
8 Correct 80 ms 16828 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 37 ms 9416 KB Output is correct
2 Correct 40 ms 16780 KB Output is correct
3 Correct 40 ms 16824 KB Output is correct
4 Correct 2 ms 3028 KB Output is correct
5 Correct 47 ms 9468 KB Output is correct
6 Correct 76 ms 9136 KB Output is correct
7 Correct 108 ms 12512 KB Output is correct
8 Correct 89 ms 10372 KB Output is correct
9 Correct 71 ms 12584 KB Output is correct
10 Correct 82 ms 12132 KB Output is correct
11 Correct 64 ms 8720 KB Output is correct
12 Correct 96 ms 10876 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 55 ms 11048 KB Output is correct
2 Correct 64 ms 17500 KB Output is correct
3 Correct 3 ms 4692 KB Output is correct
4 Correct 76 ms 10924 KB Output is correct
5 Correct 119 ms 13748 KB Output is correct
6 Correct 88 ms 10376 KB Output is correct
7 Correct 161 ms 14436 KB Output is correct
8 Correct 118 ms 12660 KB Output is correct
9 Correct 119 ms 11568 KB Output is correct
10 Correct 191 ms 15940 KB Output is correct
11 Correct 132 ms 11924 KB Output is correct
12 Correct 145 ms 13624 KB Output is correct
13 Incorrect 110 ms 10752 KB Output isn't correct
14 Halted 0 ms 0 KB -