Submission #13495

#	Time	Username	Problem	Language	Result	Execution time	Memory
13495		tncks0121	전선 연결하기 (GA9_wire)	C++14	100 / 100	536 ms	42936 KiB

wire

#include <stdio.h>
#include <stack>
#include <memory.h>
#include <assert.h>
#include <stdlib.h>
#include <algorithm>
#include <set>
#include <queue>
#include <functional>
 
using namespace std;
 
void IMPOSSIBLE() {
    puts("IMPOSSIBLE");
    exit(0);
}
 
 
const int N_ = 300500;
const int LEAF = 1<<20;
const int TSZ = LEAF + LEAF + 3;
 
int N, A[N_ + N_];
bool used[N_];
int L[N_], R[N_];
 
struct segtree {
    int tree[TSZ];
    int type;
     
    segtree (int type): type(type) {
        if(type == 1) fill(tree, tree + TSZ, -987654321);
        if(type == 2) fill(tree, tree + TSZ, [phone]);
        if(type == 3) fill(tree, tree + TSZ, 0);
    }
     
    int func (int a, int b) {
        switch(type) {
            case 1: return max(a, b);
            case 2: return min(a, b);
            case 3: return a + b;
        }
        return -1;
    }
     
    void update (int pos, int val) {
        tree[pos += LEAF] = val;
        while(pos >>= 1) tree[pos] = func(tree[pos+pos], tree[pos+pos+1]);
    }
     
    int query (int l, int r) {
        int ret = -1987654321;
        bool wr = false;
        l += LEAF; r += LEAF;
        while(l <= r) {
            if((l & 1) == 1) ret = wr ? func(ret, tree[l]) : tree[l], wr = true;
            if((r & 1) == 0) ret = wr ? func(ret, tree[r]) : tree[r], wr = true;
            l = (l + 1) >> 1;
            r = (r - 1) >> 1;
        }
        return ret;
    }
     
    // for type 3
    int kth (int k) {
        if(type != 3) return -1;
        int nd = 1;
        while(nd < LEAF) {
            if(tree[nd + nd] <= k) {
                nd = nd + nd;
            }else {
                k -= tree[nd + nd];
                nd = nd + nd + 1;
            }
        }
        return nd - LEAF;
    }
};
 
segtree tree1(1), tree2(2), tree3(3);
 
/*
        1
    2       3
  4   5   6   7
 8 9 0 1 2 3 4 5
  
  
        2
    1       1
  1   0   1   0
 0 1 0 0 0 1 0 0
 */
 
queue<int> cand, que;
vector<int> inside[N_];
stack<int> stk;
 
int res[N_ + N_];
 
void que_push(int v, int r = 1) {
    if (used[v]) return;
    que.push(v); res[v] = r; used[v] = true;
    tree1.update (L[v], -987654321);
    tree2.update (R[v], [phone]);
}
 
int main() {
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
     
    scanf("%d", &N);
    for(int i = 1; i <= N+N; i++) {
        scanf("%d", A+i);
        if(L[A[i]] == 0) L[A[i]] = i; else R[A[i]] = i;
    }
     
    for(int i = 1; i <= N; i++) {
        tree1.update (L[i], R[i]);
        tree2.update (R[i], L[i]);
    }
     
    for(int i = 1; i <= N+N; i++) {
        int a = A[i];
        if(L[a] == i) {
            int t = tree3.query(1, R[a]);
            if(tree3.tree[1] == t) cand.push(a);
            else inside[A[tree3.kth (t + 1)]].push_back(a);
            tree3.update (R[a], 0);
        }else {
            tree3.update (R[a], 1);
        }
    }
     
    int cnt = 0;
    while (cnt < N) {
        que_push(cand.front()); cand.pop();
        while (!que.empty()) {
            int u = que.front(); que.pop(); ++cnt;
             
            // 1. L[x] < L[u] < R[x] < R[u]
            for (int r; (r = tree1.query(1, L[u])) > 0;) {
                if (r < L[u]) break;
                que_push(A[r], 3 - res[u]);
            }
             
            // 2. L[u] < L[x] < R[u] < R[x]
            for (int l; (l = tree2.query(R[u], N + N)) <= N + N;) {
                if (R[u] < l) break;
                que_push(A[l], 3 - res[u]);
            }
             
            for (int i = 0; i < inside[u].size(); i++) {
                cand.push(inside[u][i]);
            }
        }
    }
     
    for (int cur = 1; cur <= 2; cur++) {
        memset(used, 0, sizeof used);
        while (!stk.empty()) stk.pop();
         
        for (int i = 1; i <= N + N; i++) if (res[A[i]] == cur) {
            if (!used[A[i]]) {
                used[A[i]] = true;
                stk.push(A[i]);
            }
            else {
                if (stk.top() != A[i]) IMPOSSIBLE();
                stk.pop();
            }
        }
    }
     
    for (int i = 1; i <= N + N; i++) printf("%c", res[A[i]] == 1 ? '^' : 'v');
    return 0;
}

• Subtask 1: 9 / 9
• Subtask 2: 15 / 15
• Subtask 3: 37 / 37
• Subtask 4: 39 / 39