最新代码
```cpp
#include <bits/stdc++.h>
using namespace std;
const int N = 20010;
int n, m, a, b, c;
vector<int> e[N];
vector<int> len[N];
queue<int>q;
int Map[N][N];
int dfn[N], low[N], tot;
int instk[N];
int scc[N], siz[N], cnt;
long long dis[N],num[N];
bool vis[N];
stack<int>st;
void tarjan(int x) {
dfn[x] = low[x] = ++tot;
st.push(x);
instk[x] = 1;
for (int y : e[x]) {
if (!dfn[y]) {
tarjan(y);
low[x] = min(low[x], low[y]);
} else if (instk[y])
low[x] = min(low[x], dfn[y]);
}
if (dfn[x] == low[x]) {
int y;
++cnt;
do {
y = st.top();
st.pop();
instk[y] = 0;
scc[y] = cnt;
++siz[cnt];
} while (y != x);
}
}
void SPFA(int x) {
while (q.size()) q.pop();
for (int i = 1; i <= cnt; i++) {
dis[i] = INT_MAX;
}
dis[x] = 0;
q.push(x);
while (!q.empty()) {
int temp = q.front();
q.pop();
for (int j = 1; j <= cnt; j++) {
if (dis[j] > Map[temp][j] + dis[temp]) {
dis[j] = dis[temp] + Map[temp][j];
if (!vis[j]) {
q.push(j);
vis[j] = 1;
num[j]++;
}
}
}
vis[temp] = 0;
}
}
int main() {
cin >> n >> m;
while (m--)
cin >> a >> b >> c, e[a].push_back(b), len[a].push_back(c);
for (int i = 1; i <= n; i++)
if (!dfn[i]) tarjan(i);
for (int i = 1; i <= cnt; i++)
for (int j = 1; j <= cnt; j++)
Map[i][j] = INT_MAX;
for (int i = 1; i <= cnt; i++) Map[i][i] = 0;
for (int i = 1; i <= n; i++)
for (unsigned int j = 0 ; j < e[i].size(); j++)
if (scc[i] == scc[e[i][j]])
Map[scc[i]][scc[e[i][j]]] = 0;
else
Map[scc[i]][scc[e[i][j]]] = min(Map[i][scc[e[i][j]]], len[i][j]);
SPFA(scc[1]);
cout << dis[scc[n]];
return 0;
}
by kimi0705 @ 2022-12-26 18:36:45
@[EndCentury](/user/320616) 我测的是对的
by kimi0705 @ 2023-01-01 15:54:13
```
3 3
1 2 1
2 3 1
3 1 1
0
--------------------------------
Process exited after 0.721 seconds with return value 0, 71212 KB mem used.
Press ANY key to exit...
```
by kimi0705 @ 2023-01-01 15:54:51
3 3
1 2 1
2 3 1
1 3 4
by EndCentury @ 2023-01-01 16:05:34
```
#include <bits/stdc++.h>
using namespace std;
const int N = 20010;
int n, m, a, b, c;
vector<int> e[N];
vector<int> len[N];
queue<int>q;
int Map[N][N];
int dfn[N], low[N], tot;
int instk[N];
int scc[N], siz[N], cnt;
long long dis[N],num[N];
bool vis[N];
stack<int>st;
void tarjan(int x) {
dfn[x] = low[x] = ++tot;
st.push(x);
instk[x] = 1;
for (int y : e[x]) {
if (!dfn[y]) {
tarjan(y);
low[x] = min(low[x], low[y]);
} else if (instk[y])
low[x] = min(low[x], dfn[y]);
}
if (dfn[x] == low[x]) {
int y;
++cnt;
do {
y = st.top();
st.pop();
instk[y] = 0;
scc[y] = cnt;
++siz[cnt];
} while (y != x);
}
}
void SPFA(int x) {
while (q.size()) q.pop();
for (int i = 1; i <= cnt; i++) {
dis[i] = INT_MAX;
}
dis[x] = 0;
q.push(x);
while (!q.empty()) {
int temp = q.front();
q.pop();
for (int j = 1; j <= cnt; j++) {
if (dis[j] > Map[temp][j] + dis[temp]) {
dis[j] = dis[temp] + Map[temp][j];
if (!vis[j]) {
q.push(j);
vis[j] = 1;
num[j]++;
}
}
}
vis[temp] = 0;
}
}
int main() {
cin >> n >> m;
while (m--)
cin >> a >> b >> c, e[a].push_back(b), len[a].push_back(c);
for (int i = 1; i <= n; i++)
if (!dfn[i]) tarjan(i);
for (int i = 1; i <= cnt; i++)
for (int j = 1; j <= cnt; j++)
Map[i][j] = INT_MAX;
for (int i = 1; i <= cnt; i++) Map[i][i] = 0;
for (int i = 1; i <= n; i++)
for (unsigned int j = 0 ; j < e[i].size(); j++)
if (scc[i] == scc[e[i][j]])
Map[scc[i]][scc[e[i][j]]] = 0x3f3f3f3f;
else
Map[scc[i]][scc[e[i][j]]] = len[i][j];
SPFA(scc[1]);
cout << dis[scc[n]];
return 0;
}
```
79分。。。
by EndCentury @ 2023-01-01 16:06:54
你改了哪里？
by kimi0705 @ 2023-01-01 16:31:00
为什么要把那个len啊？改成最大值？还有为什么要把那个min去掉
by kimi0705 @ 2023-01-01 16:33:04
他不做成了一个点吗
by kimi0705 @ 2023-01-01 16:33:34
自己点到自己点距离应该零啊
by kimi0705 @ 2023-01-01 16:34:33
@[EndCentury](/user/320616)
by kimi0705 @ 2023-01-01 16:35:02