답안 #581909

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
581909 2022-06-23T07:58:55 Z 조영욱(#8367) 전압 (JOI14_voltage) C++14
45 / 100
199 ms 17516 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=1;i<=n;i++){
        if (!vis[i]) {
            dfs2(i,d+1);
        }
        //printf("%d ",value[i]);
    }
    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);
      |         ~~~~~^~~~~~~~~~~~~~~
# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 3156 KB Output is correct
2 Correct 2 ms 3028 KB Output is correct
3 Correct 3 ms 3028 KB Output is correct
4 Correct 3 ms 3028 KB Output is correct
5 Correct 3 ms 3120 KB Output is correct
6 Correct 3 ms 3156 KB Output is correct
7 Correct 3 ms 3156 KB Output is correct
8 Incorrect 3 ms 3156 KB Output isn't correct
9 Halted 0 ms 0 KB -
# 결과 실행 시간 메모리 Grader output
1 Correct 65 ms 9436 KB Output is correct
2 Correct 76 ms 13600 KB Output is correct
3 Correct 48 ms 9208 KB Output is correct
4 Correct 116 ms 13500 KB Output is correct
5 Correct 7 ms 3924 KB Output is correct
6 Correct 107 ms 11556 KB Output is correct
7 Correct 95 ms 13768 KB Output is correct
8 Correct 116 ms 16864 KB Output is correct
# 결과 실행 시간 메모리 Grader output
1 Correct 38 ms 9380 KB Output is correct
2 Correct 41 ms 16824 KB Output is correct
3 Correct 49 ms 16720 KB Output is correct
4 Correct 3 ms 3028 KB Output is correct
5 Correct 49 ms 9488 KB Output is correct
6 Correct 89 ms 9008 KB Output is correct
7 Correct 120 ms 12460 KB Output is correct
8 Correct 75 ms 10372 KB Output is correct
9 Correct 100 ms 12516 KB Output is correct
10 Correct 96 ms 12208 KB Output is correct
11 Correct 73 ms 8640 KB Output is correct
12 Correct 94 ms 10976 KB Output is correct
# 결과 실행 시간 메모리 Grader output
1 Correct 49 ms 11088 KB Output is correct
2 Correct 67 ms 17516 KB Output is correct
3 Correct 4 ms 4692 KB Output is correct
4 Correct 123 ms 10980 KB Output is correct
5 Correct 97 ms 13892 KB Output is correct
6 Correct 102 ms 10660 KB Output is correct
7 Correct 156 ms 14540 KB Output is correct
8 Correct 192 ms 12716 KB Output is correct
9 Correct 136 ms 11652 KB Output is correct
10 Correct 191 ms 16100 KB Output is correct
11 Correct 199 ms 11948 KB Output is correct
12 Correct 161 ms 13752 KB Output is correct
13 Incorrect 118 ms 11884 KB Output isn't correct
14 Halted 0 ms 0 KB -