Hi, ↵
↵
About three weeks ago, I asked a related question [here](https://codeforces.me/blog/entry/84772). In that post, my program output to stdout, while it needs to be output into a file. A lot of people gives me suggestions to use ↵
```freopen("Filename.in", "r", stdin); freopen("Filename.out", "w", stdout);``` instead of ```ifstream``` ...↵
↵
↵
That's what I did and things have been ok for the past three weeks. However, when I tried to submit a solution using ```freopen"```, this happens:↵
↵
↵
↵
↵
I go check my solution and find no error that would cause "runtime error or memory limited exceeded". Therefore, I submitted it again, only replacing ```freopen``` with ```ifstream```. Then, it gets accepted:↵
↵
. ↵
↵
This might be a noobish question, but what causes this and how can I avoid that? Thank you!↵
↵
P.S. This is the code: ↵
↵
```↵
#include<bits/stdc++.h>↵
#define ll long long↵
#define rep(i, m, n) for (int i = m; i <= n; i++)↵
#define per(i, m, n) for (int i = m; i >= n; i--)↵
#define FOR(i, m, n, k) for (int i = m; i <= n; i += k)↵
#define ROF(i, m, n, k) for (int i = m; i >= n; i -= k)↵
#define pb push_back↵
#define mp make_pair↵
#define pii pair<int, int>↵
#define all(v) v.begin(), v.end()↵
#define INF 0x3f3f3f3f↵
using namespace std;↵
↵
const int maxn = 3e4 + 10;↵
↵
struct edge {↵
int to, cost;↵
};↵
↵
int N, T;↵
int a[105][105], dx[4] = {1, -1, 0, 0}, dy[4] = {0, 0, 1, -1};↵
int dis[maxn];↵
vector<edge> G[maxn];↵
↵
int get(int x, int y, int t) {↵
return (x - 1) * N + y + t * N * N;↵
}↵
↵
void dijkstra(int s) {↵
priority_queue<pii, vector<pii>, greater<pii> > q;↵
memset(dis, INF, sizeof(dis));↵
dis[s] = 0;↵
q.push(make_pair(0, s));↵
while (!q.empty()) {↵
pii p = q.top();↵
q.pop();↵
int u = p.second;↵
if (dis[u] < p.first) continue;↵
for (auto node : G[u]) {↵
int v = node.to;↵
if (dis[v] > dis[u] + node.cost) {↵
dis[v] = dis[u] + node.cost;↵
q.push(make_pair(dis[v], v));↵
}↵
}↵
}↵
}↵
↵
int main() {↵
ios::sync_with_stdio(false);↵
cin.tie(0); cout.tie(0);↵
// ifstream cin("visitfj.in");↵
// ofstream cout("visitfj.out");↵
freopen("visistfj.in", "r", stdin);↵
freopen("visistfj.out", "w", stdout);↵
cin >> N >> T;↵
rep(i, 1, N) rep(j, 1, N) cin >> a[i][j];↵
rep(i, 1, N) {↵
rep(j, 1, N) {↵
rep(k, 0, 3) {↵
int x = i + dx[k], y = j + dy[k];↵
if (x < 1 || x > N || y < 1 || y > N) continue;↵
rep(t, 0, 2) {↵
int nxt = (t + 1) % 3;↵
int cost = T + ((nxt == 0) ? a[x][y] : 0);↵
G[get(i, j, t)].pb((edge) {get(x, y, nxt), cost});↵
}↵
}↵
}↵
}↵
dijkstra(get(1, 1, 0));↵
int ans = INF;↵
rep(i, 0, 2) ans = min(dis[get(N, N, i)], ans);↵
cout << ans << "\n";↵
return 0;↵
}↵
```↵
↵
↵
About three weeks ago, I asked a related question [here](https://codeforces.me/blog/entry/84772). In that post, my program output to stdout, while it needs to be output into a file. A lot of people gives me suggestions to use ↵
```freopen("Filename.in", "r", stdin); freopen("Filename.out", "w", stdout);``` instead of ```ifstream``` ...↵
↵
↵
That's what I did and things have been ok for the past three weeks. However, when I tried to submit a solution using ```freopen
↵
↵
↵
↵
I go check my solution and find no error that would cause "runtime error or memory limited exceeded". Therefore, I submitted it again, only replacing ```freopen``` with ```ifstream```. Then, it gets accepted:↵
↵
. ↵
↵
This might be a noobish question, but what causes this and how can I avoid that? Thank you!↵
↵
P.S. This is the code: ↵
↵
```↵
#include<bits/stdc++.h>↵
#define ll long long↵
#define rep(i, m, n) for (int i = m; i <= n; i++)↵
#define per(i, m, n) for (int i = m; i >= n; i--)↵
#define FOR(i, m, n, k) for (int i = m; i <= n; i += k)↵
#define ROF(i, m, n, k) for (int i = m; i >= n; i -= k)↵
#define pb push_back↵
#define mp make_pair↵
#define pii pair<int, int>↵
#define all(v) v.begin(), v.end()↵
#define INF 0x3f3f3f3f↵
using namespace std;↵
↵
const int maxn = 3e4 + 10;↵
↵
struct edge {↵
int to, cost;↵
};↵
↵
int N, T;↵
int a[105][105], dx[4] = {1, -1, 0, 0}, dy[4] = {0, 0, 1, -1};↵
int dis[maxn];↵
vector<edge> G[maxn];↵
↵
int get(int x, int y, int t) {↵
return (x - 1) * N + y + t * N * N;↵
}↵
↵
void dijkstra(int s) {↵
priority_queue<pii, vector<pii>, greater<pii> > q;↵
memset(dis, INF, sizeof(dis));↵
dis[s] = 0;↵
q.push(make_pair(0, s));↵
while (!q.empty()) {↵
pii p = q.top();↵
q.pop();↵
int u = p.second;↵
if (dis[u] < p.first) continue;↵
for (auto node : G[u]) {↵
int v = node.to;↵
if (dis[v] > dis[u] + node.cost) {↵
dis[v] = dis[u] + node.cost;↵
q.push(make_pair(dis[v], v));↵
}↵
}↵
}↵
}↵
↵
int main() {↵
ios::sync_with_stdio(false);↵
cin.tie(0); cout.tie(0);↵
// ifstream cin("visitfj.in");↵
// ofstream cout("visitfj.out");↵
freopen("visistfj.in", "r", stdin);↵
freopen("visistfj.out", "w", stdout);↵
cin >> N >> T;↵
rep(i, 1, N) rep(j, 1, N) cin >> a[i][j];↵
rep(i, 1, N) {↵
rep(j, 1, N) {↵
rep(k, 0, 3) {↵
int x = i + dx[k], y = j + dy[k];↵
if (x < 1 || x > N || y < 1 || y > N) continue;↵
rep(t, 0, 2) {↵
int nxt = (t + 1) % 3;↵
int cost = T + ((nxt == 0) ? a[x][y] : 0);↵
G[get(i, j, t)].pb((edge) {get(x, y, nxt), cost});↵
}↵
}↵
}↵
}↵
dijkstra(get(1, 1, 0));↵
int ans = INF;↵
rep(i, 0, 2) ans = min(dis[get(N, N, i)], ans);↵
cout << ans << "\n";↵
return 0;↵
}↵
```↵
↵
