Submission #364526

#	Time	Username	Problem	Language	Result	Execution time	Memory
364526		cpp219	Olympic Bus (JOI20_ho_t4)	C++14	0 / 100	167 ms	262148 KiB

ho_t4

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define fs first
#define sc second
using namespace std;
const ll N = 200 + 6;
const ll inf = 1e13 + 7;
typedef pair<int,int> LL;

struct edge{
    int v,c,id;
};
vector<edge> g[N],rg[N];
int n,m,u,v,c,inv,banned;
ll ans = inf,d[N],D[4][N];
bool dd[N],spec[100000];
void cond_to_all(ll scr,ll cond,ll Is_in){
    memset(dd,0,sizeof(dd)); fill(d,d + n + 1,inf);
    d[scr] = 0;
    while(1){
        ll x = inf,u = -1;
        for (ll i = 1;i <= n;i++) if (d[i] < x && !dd[i]) x = d[i],u = i;
        if (u == -1) break; dd[u] = 1;
        for (auto i : g[u]){
            ll v = i.v,L = i.c;
            if (d[v] > d[u] + L && i.id != banned){
                d[v] = d[u] + L;
            }
        }
    }
    for (ll i = 1;i <= n;i++) D[cond][i] = d[i];
}

void all_to_cond(ll scr,ll cond,ll Is_in){
    memset(dd,0,sizeof(dd)); fill(d,d + n + 1,inf);
    d[scr] = 0;
    while(1){
        ll x = inf,u = -1;
        for (ll i = 1;i <= n;i++) if (d[i] < x && !dd[i]) x = d[i],u = i;
        if (u == -1) break; dd[u] = 1;
        for (auto i : rg[u]){
            ll v = i.v,L = i.c;
            if (d[v] > d[u] + L && i.id != banned){
                d[v] = d[u] + L;
            }
        }
    }
    for (ll i = 1;i <= n;i++) D[cond][i] = d[i];
}

struct Road{
    ll u,v,c,inv;
};
Road a[100000];

void Rev(ll id){
    banned = id;
    u = a[id].u; v = a[id].v; c = a[id].c;
    g[v].push_back({u,c,m + 1}); rg[u].push_back({v,c,m + 1});
    cond_to_all(1,0,0); cond_to_all(n,2,0); all_to_cond(1,1,0); all_to_cond(n,3,0);
    ans = min(ans,D[0][n] + D[2][1] + a[id].inv);
    g[v].pop_back(); rg[u].pop_back(); banned = 0;
    cond_to_all(1,0,0); cond_to_all(n,2,0); all_to_cond(1,1,0); all_to_cond(n,3,0);
}
/// 0 : 1 to all    1 : all to 1    2 : n to all    3 : all to n

void Trace(ll now,ll cond){
    if (cond == 0||cond == 2){
        for (auto i : g[now]){
            ll v = i.v,L = i.c;
            if (D[cond][v] == D[cond][now] + L) spec[i.id] = 1,Trace(v,cond);
        }
    }
    else{
        for (auto i : rg[now]){
            ll v = i.v,L = i.c;
            if (D[cond][v] == D[cond][now] + L) spec[i.id] = 1,Trace(v,cond);
        }
    }
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    #define task "tst"
    if (fopen(task".INP","r")){
        freopen(task".INP","r",stdin);
        //freopen(task".OUT","w",stdout);
    }
    cin>>n>>m;
    for (ll i = 1;i <= m;i++){
        cin>>u>>v>>c>>inv; a[i] = {u,v,c,inv};
        g[u].push_back({v,c,i}); rg[v].push_back({u,c,i});
    }
    cond_to_all(1,0,1); cond_to_all(n,2,1); all_to_cond(1,1,1); all_to_cond(n,3,1);
    Trace(1,0); Trace(n,2); Trace(1,1); Trace(n,3); return 0;
    ll cnt = 0;
    for (ll i = 1;i <= m;i++) cnt += spec[i],cout<<spec[i]<<" "; cout<<cnt; return 0;
    assert(cnt <= 4*n); return 0;
    ans = D[0][n] + D[2][1]; //cout<<ans; return 0;
    for (ll i = 1;i <= m;i++){
        u = a[i].u; v = a[i].v; c = a[i].c;
        if (!spec[i]){
            //cout<<D[2][1]; return 0;
            ll p = min(D[0][n],D[0][v] + c + D[3][u]),q = min(D[2][1],D[2][v] + c + D[1][u]);
            ans = min(ans,p + q + a[i].inv); //cout<<p<<" x "<<D[2][v]; return 0;
        }
        else Rev(i);
    }
    cout<<(ans >= inf ? -1 : ans);
}

Compilation message (stderr)

ho_t4.cpp: In function 'void cond_to_all(long long int, long long int, long long int)':
ho_t4.cpp:24:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   24 |         if (u == -1) break; dd[u] = 1;
      |         ^~
ho_t4.cpp:24:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   24 |         if (u == -1) break; dd[u] = 1;
      |                             ^~
ho_t4.cpp: In function 'void all_to_cond(long long int, long long int, long long int)':
ho_t4.cpp:41:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   41 |         if (u == -1) break; dd[u] = 1;
      |         ^~
ho_t4.cpp:41:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   41 |         if (u == -1) break; dd[u] = 1;
      |                             ^~
ho_t4.cpp: In function 'int main()':
ho_t4.cpp:94:29: warning: narrowing conversion of 'i' from 'long long int' to 'int' [-Wnarrowing]
   94 |         g[u].push_back({v,c,i}); rg[v].push_back({u,c,i});
      |                             ^
ho_t4.cpp:94:55: warning: narrowing conversion of 'i' from 'long long int' to 'int' [-Wnarrowing]
   94 |         g[u].push_back({v,c,i}); rg[v].push_back({u,c,i});
      |                                                       ^
ho_t4.cpp:99:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   99 |     for (ll i = 1;i <= m;i++) cnt += spec[i],cout<<spec[i]<<" "; cout<<cnt; return 0;
      |     ^~~
ho_t4.cpp:99:66: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   99 |     for (ll i = 1;i <= m;i++) cnt += spec[i],cout<<spec[i]<<" "; cout<<cnt; return 0;
      |                                                                  ^~~~
ho_t4.cpp:88:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   88 |         freopen(task".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 63