Create 3562_jianrenfang.cpp

From http://www.cnblogs.com/jianrenfang/p/5723349.html

SDUTOJ/3562_jianrenfang.cpp

@@ -0,0 +1,97 @@
+#include <iostream>
+#include <cstdio>
+#include <cstdlib>
+#include <cmath>
+#include <algorithm>
+#include <climits>
+#include <cstring>
+#include <string>
+#include <set>
+#include <map>
+#include <queue>
+#include <stack>
+#include <vector>
+#include <list>
+#define mod 1000000007
+#define inf 0x3f3f3f3f
+#define pi acos(-1.0)
+using namespace std;
+typedef long long ll;
+#define RANGE 1005
+#define MAX 0x3f3f3f3f
+int cost[RANGE][RANGE];
+int d[RANGE];
+bool used[RANGE];
+int n,m;
+int pre[1005];
+void spfa(int s)
+{
+    int i,j,now;
+    for(i=0;i<=n+1;i++)
+    {
+        d[i]=MAX;
+        used[i]=false;
+    }
+    int flag=0;
+    for(i=0;i<=n+1;i++)
+    {
+        if(cost[0][i]<MAX)pre[i]=i;//初始化pre数组
+    }
+    used[s]=true;
+    d[s]=0;
+    queue<int> q;
+    q.push(s);
+    while(!q.empty())
+    {
+        now=q.front();
+        q.pop();
+        for(i=0;i<=n+1;i++)
+        {
+            if(d[i]>d[now]+cost[now][i])
+            {
+                d[i]=d[now]+cost[now][i];
+                if(used[i]==0)
+                {
+                    if(now!=0)pre[i]=pre[now];
+                    used[i]==true;
+                    q.push(i);
+                }
+            }
+            if(d[i]==d[now]+cost[now][i])
+            {
+                    if(now!=0)pre[i]=min(pre[i],pre[now]);
+            }
+        }
+    }
+}
+int main()
+{
+    int i,j,a,b,c;
+    int we;
+    scanf("%d",&we);
+    while(we--)
+    {scanf("%d%d",&n,&m);
+        if(!n&&!m) break;
+        for(i=0;i<=n+1;++i)
+        {
+            for(j=0;j<=i;j++)
+            {
+                if(i==j)  cost[i][j]=0;
+                else  cost[i][j]=cost[j][i]=MAX;
+            }
+        }
+        for(i=0;i<m;i++)
+        {
+            scanf("%d%d%d",&a,&b,&c);
+            cost[a][b]=c;
+        }
+        spfa(0);
+        if(d[n+1]<MAX)
+        {
+            if(pre[n+1]==n+1)printf("0\n");
+            else printf("%d\n",pre[n+1]);
+        }
+        else printf("-1\n");
+    }
+    return 0;
+}