Submission #249247

#	Time	Username	Problem	Language	Result	Execution time	Memory
249247		rdd6584	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	100 / 100	384 ms	126968 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;
typedef pair<int ,int> pii;


char visit[30000];
unordered_map<int,int> dist[30000];
int dp[30000][1000]; // 거리 100 이하일 때,
vector<int> v[30000];

int main() {
    int n, m;
    scanf("%d %d", &n, &m);

    int st, ed;
    for (int i = 0; i < m; i++) {
        int a,b;
        scanf("%d %d" ,&a, &b);
        v[a].push_back(b);
        if (i==0) st = a;
        else if (i==1) ed = a;
    }

    memset(dp, -1, sizeof(dp));
    queue<pii> q;
    for (int i : v[st]) {
        if (i < 1000) dp[st][i] = 0;
        else dist[st][i] = 0;
        q.push({st, i});
    }

    while (!q.empty()) {
        pii tv = q.front();
        q.pop();

        int me;
        if (tv.second < 1000) me = dp[tv.first][tv.second];
        else me = dist[tv.first][tv.second];

        if (tv.first == ed) return !printf("%d", me);
        int ne;

        if (tv.second < 1000) {
            for (int dir = -1; dir <= 1; dir += 2) {
                ne = tv.first + dir * tv.second;
                if (ne < 0 || ne >= n) continue;
                if (dp[ne][tv.second] == -1) {
                    int flag = 0;
                    if (!visit[ne]) {
                        visit[ne] = 1;
                        for (int i : v[ne]) {
                            if (i < 1000) dp[ne][i] = me + 1;
                            else dist[ne][i] = me + 1;
                            q.push({ne, i});
                            flag |= i == tv.second;
                        }
                    }
                    if (!flag) {
                        q.push({ne, tv.second});
                        dp[ne][tv.second] = me + 1;
                    }
                }
            }
        }
        else {
            for (int dir = -1; dir <= 1; dir += 2) {
                ne = tv.first + dir * tv.second;
                if (ne < 0 || ne >= n) continue;
                if (dist[ne].find(tv.second) == dist[ne].end()) {
                    int flag = 0;
                    if (!visit[ne]) {
                        visit[ne] = 1;
                        for (int i : v[ne]) {
                            if (i < 1000) dp[ne][i] = me + 1;
                            else dist[ne][i] = me + 1;
                            q.push({ne, i});
                            flag |= i == tv.second;
                        }
                    }
                    if (!flag) {
                        q.push({ne, tv.second});
                        dist[ne][tv.second] = me + 1;
                    }
                }
            }
        }
    }
    printf("-1");
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:13:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~~
skyscraper.cpp:18:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d" ,&a, &b);
         ~~~~~^~~~~~~~~~~~~~~~~
skyscraper.cpp:15:9: warning: 'st' may be used uninitialized in this function [-Wmaybe-uninitialized]
     int st, ed;
         ^~
skyscraper.cpp:40:9: warning: 'ed' may be used uninitialized in this function [-Wmaybe-uninitialized]
         if (tv.first == ed) return !printf("%d", me);
         ^~

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 14 / 14
• Subtask 4: 21 / 21
• Subtask 5: 43 / 43