제출 #951539

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
951539		Nhoksocqt1	자매 도시 (APIO20_swap)	C++17	50 / 100	2013 ms	25196 KiB

swap

#include<bits/stdc++.h>
using namespace std;

#define inf 0x3f3f3f3f
#define sz(x) int((x).size())
#define fi first
#define se second
typedef long long ll;
typedef pair<int, int> ii;

template<class X, class Y>
	inline bool maximize(X &x, const Y &y) {return (x < y ? x = y, 1 : 0);}
template<class X, class Y>
	inline bool minimize(X &x, const Y &y) {return (x > y ? x = y, 1 : 0);}

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int Random(int l, int r) {
    return uniform_int_distribution<int>(l, r)(rng);
}

const int MAXN = 100005;

struct Edge {
    int u, v, w;
} edge[2 * MAXN];

ii minw[3];
vector<ii> adj[MAXN];
int pa[MAXN], wEdge[MAXN], cntLeaf[MAXN], maxw, numNode, numEdge;
bool dp[1003][1003], dx[MAXN], check_sub1, check_sub2;

void init(int _N, int _M, vector<int> _U, vector<int> _V, vector<int> _W) {
    numNode = _N, numEdge = _M;

    minw[0] = minw[1] = minw[2] = {1e9+7, -1};
    check_sub2 = (numEdge + 1 == numNode);
    for (int i = 0; i < numEdge; ++i) {
        edge[i] = {_U[i], _V[i], _W[i]};
        adj[edge[i].u].push_back(ii(edge[i].v, edge[i].w));
        adj[edge[i].v].push_back(ii(edge[i].u, edge[i].w));
        check_sub2 &= (edge[i].u == 0);
        maxw = max(maxw, edge[i].w);

        wEdge[edge[i].v] = edge[i].w;
        if(minw[0].fi > edge[i].w) {
            minw[2] = minw[1], minw[1] = minw[0];
            minw[0] = {edge[i].w, edge[i].v};
        } else
            if(minw[1].fi > edge[i].w) {
                minw[2] = minw[1];
                minw[1] = {edge[i].w, edge[i].v};
            } else
                if(minw[2].fi > edge[i].w) {
                    minw[2] = {edge[i].w, edge[i].v};
                }
    }

    check_sub1 = 1;
    for (int i = 0; i < numNode; ++i)
        check_sub1 &= (sz(adj[i]) <= 2);

    sort(edge, edge + numEdge, [](const Edge &a, const Edge &b) {
        return (a.w < b.w);
    });
}

int sub2(int x, int y) {
    if(numNode <= 3)
        return -1;

    int res = max(wEdge[x], wEdge[y]), cnt(1 + (x == 0));
    for (int k = 0; k < 3; ++k) {
        if(minw[k].se != x && minw[k].se != y) {
            if(--cnt == 0) {
                res = max(res, minw[k].fi);
                break;
            }
        }
    }

    return res;
}

int sub3(int x, int y) {
    int l(0), r(numEdge - 1), ans(-1);
    while(l <= r) {
        int mid = (l + r) >> 1;
        for (int i = 0; i < numNode; ++i) {
            for (int j = 0; j < numNode; ++j)
                dp[i][j] = 0;
        }

        queue<ii> qu;
        qu.push(ii(x, y));
        dp[x][y] = 1;

        int xt(x), yt(y);
        bool check(0);
        while(sz(qu)) {
            int x(qu.front().fi), y(qu.front().se);
            qu.pop();

            if(x == yt && y == xt) {
                check = 1;
                break;
            }

            for (int it = 0; it < sz(adj[x]); ++it) {
                int w(adj[x][it].fi), c(adj[x][it].se);
                if(c <= edge[mid].w && !dp[w][y] && w != y) {
                    dp[w][y] = 1;
                    qu.push(ii(w, y));
                }
            }

            for (int it = 0; it < sz(adj[y]); ++it) {
                int w(adj[y][it].fi), c(adj[y][it].se);
                if(c <= edge[mid].w && !dp[x][w] && x != w) {
                    dp[x][w] = 1;
                    qu.push(ii(x, w));
                }
            }
        }

        if(check) {
            ans = edge[mid].w;
            r = mid - 1;
        } else {
            l = mid + 1;
        }
    }


    return ans;
}

ii dfs(int u) {
    dx[u] = 1;
    cntLeaf[u] = 0;
    ii res = {sz(adj[u]), 1};
    for (int it = 0; it < sz(adj[u]); ++it) {
        int v(adj[u][it].fi);
        if(!dx[v]) {
            pa[v] = u;
            ii tmp = dfs(v);
            res = {res.fi + tmp.fi, res.se + tmp.se};
            cntLeaf[u] += cntLeaf[v];
        }
    }

    if(cntLeaf[u] == 0)
        cntLeaf[u] = 1;

    return res;
}

int sub4(int x, int y) {
    int l(0), r(numEdge - 1), ans(-1);
    while(l <= r) {
        int mid = (l + r) >> 1;

        for (int i = 0; i < numNode; ++i) {
            adj[i].clear();
            dx[i] = 0;
        }

        for (int i = 0; i <= mid; ++i) {
            int u(edge[i].u), v(edge[i].v);
            adj[u].push_back(ii(v, 0));
            adj[v].push_back(ii(u, 0));
        }

        pa[x] = -1;
        ii res = dfs(x);
        bool check(0);
        if(dx[y]) {
            int u(y);
            while(pa[u] != x)
                u = pa[u];

            check = (res.fi / 2 >= res.se || cntLeaf[y] > 1 || cntLeaf[x] - cntLeaf[u] > 1 || cntLeaf[u] - cntLeaf[y] > 0);
            //cout << edge[mid].w << ' ' << res.fi << ' ' << res.se << ' ' << cntLeaf[x] << ' ' << cntLeaf[y] << ' ' << cntLeaf[u] << '\n';
        }

        if(check) {
            ans = edge[mid].w;
            r = mid - 1;
        } else {
            l = mid + 1;
        }
    }

    return ans;
}

int getMinimumFuelCapacity(int x, int y) {
    if(check_sub1)
        return (numNode == numEdge) ? maxw : -1;

    if(check_sub2)
        return sub2(x, y);

    if(numNode <= 1000)
        return sub3(x, y);

    return sub4(x, y);
}

#ifdef Nhoksocqt1

int main(void) {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    #define TASK "swap"
    if(fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }

    vector<int> _U, _V, _W;
    int _N, _M, _Q;
    cin >> _N >> _M >> _Q;

    _U.resize(_M), _V.resize(_M), _W.resize(_M);
    for (int i = 0; i < _M; ++i) {
        cin >> _U[i] >> _V[i] >> _W[i];
    }

    init(_N, _M, _U, _V, _W);
    for (int t = 0; t < _Q; ++t) {
        int _X, _Y;
        cin >> _X >> _Y;
        cout << "MINIMUM FUEL CAPACITY " << _X << " TO " << _Y << ": " << getMinimumFuelCapacity(_X, _Y) << '\n';
    }

    return 0;
}

#endif // Nhoksocqt1

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• Subtask 4: 20 / 20
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