Submission #418106

#	Time	Username	Problem	Language	Result	Execution time	Memory
418106		juggernaut	Paths (BOI18_paths)	C++17	20 / 100	271 ms	21924 KiB

paths

#include<bits/stdc++.h>
#define fr first
#define sc second
using namespace std;
void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
typedef long long ll;
#define USING_ORDERED_SET 0
#if USING_ORDERED_SET
#include<bits/extc++.h>
using namespace __gnu_pbds;
template<class T>using ordered_set=tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
#endif
template<class T>void umax(T &a,T b){if(a<b)a=b;}
template<class T>void umin(T &a,T b){if(b<a)a=b;}
#ifdef IOI2021SG
    #define printl(args...)printf(args)
#else
    #define printl(args...)((void)0)
#endif
int n,m,k;
int a[300005];
vector<int>g[300005];
ll ans;
int cnt[6];
int main(){
    scanf("%d%d%d",&n,&m,&k);
    for(int i=1;i<=n;i++)scanf("%d",&a[i]);
    while(m--){
        int x,y;
        scanf("%d%d",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    if(k==1)puts("0");
    else if(k==2){
        for(int i=1;i<=n;i++)for(int to:g[i])if(a[to]!=a[i])ans++;
        printf("%lld",ans);
    }else if(k==3){
        for(int i=1;i<=n;i++)for(int to:g[i])if(a[to]!=a[i])ans++;
        for(int i=1;i<=n;i++){
            cnt[1]=cnt[2]=cnt[3]=0;
            int all=0;
            for(int to:g[i])if(a[to]!=a[i])cnt[a[to]]++,all++;
            for(int to:g[i])if(a[to]!=a[i])ans+=all-cnt[a[to]];
        }
        printf("%lld",ans);
    }
}

Compilation message (stderr)

paths.cpp: In function 'void usaco(std::string)':
paths.cpp:5:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 | void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
paths.cpp:5:66: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 | void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
      |                                                           ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
paths.cpp: In function 'int main()':
paths.cpp:26:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 |     scanf("%d%d%d",&n,&m,&k);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~
paths.cpp:27:31: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |     for(int i=1;i<=n;i++)scanf("%d",&a[i]);
      |                          ~~~~~^~~~~~~~~~~~
paths.cpp:30:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |         scanf("%d%d",&x,&y);
      |         ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 0 / 23
• Subtask 2: 20 / 20
• Subtask 3: 0 / 27
• Subtask 4: 0 / 30