제출 #448481

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
448481		zxcvbnm	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	컴파일 에러	0 ms	0 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int nax = 30005;
const int INF = 1e9 + 5;
vector<int> dog[nax];
vector<int> jump(nax);
ll dp[2005][nax];
int n, m;
int go(int sky, int doge) {
    if (sky < 0 || sky >= n) return INF;
    if (doge == 1) return 0;

    int& ret = dp[sky][doge];
    if (ret != -1) {
        return ret;
    }

    ret = INF;
    // pass news
    for(int i : dog[sky]) {
        ret = min(ret, go(sky, i));
    }

    // jump left
    if (sky-jump[doge] >= 0) {
        ret = min(ret, 1+go(sky-jump[doge], doge));
    }
    // jump right
    if (sky+jump[doge] < n) {
        ret = min(ret, 1+go(sky+jump[doge], doge));
    }

    return ret;
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    memset(dp, -1, sizeof dp);

    cin >> n >> m;
    int boss = 0;
    for(int i = 0; i < m; i++) {
        int idx, p;
        cin >> idx >> p;
        dog[idx].push_back(i);
        jump[i] = p;
        if (i == 0) {
            boss = idx;
        }
    }

    int ans = go(boss, 0);
    if (ans >= INF) {
        cout << -1 << "\n";
    } else {
        cout << ans << "\n";
    }
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

skyscraper.cpp: In function 'int go(int, int)':
skyscraper.cpp:14:28: error: cannot bind non-const lvalue reference of type 'int&' to an rvalue of type 'int'
   14 |     int& ret = dp[sky][doge];
      |                ~~~~~~~~~~~~^