Create hdu4405.cpp

hdu4405.cpp

@@ -0,0 +1,41 @@
+#include <iostream>
+#include <cstdio>
+#include <stdlib.h>
+#include <string.h>
+#include <string>
+#include <algorithm>
+#include <math.h>
+using namespace std;
+double e[100100];
+int f[100100];
+int main()
+{
+    int n, m;
+    while(scanf("%d%d", &n, &m) != EOF && (n != 0 || m != 0))
+    {
+        for(int i = 0; i <= n; i++)
+            e[i] = 0;
+        memset(f, -1, sizeof(f));
+        for(int i = 0; i < m; i++)
+        {
+            int a, b;
+            scanf("%d%d", &a, &b);
+            f[a] = b;
+        }
+        for(int i = n - 1; i >= 0; i--)
+        {
+            if(f[i] != -1) e[i] = e[f[i]];
+            else
+            {
+                for(int j = 1; j <= 6; j++)
+                {
+                    if(i + j <= n) e[i] += (1.0 / 6) * e[i + j];
+                }
+                e[i] += 1.0;
+            }
+        }
+        printf("%.4lf\n", e[0]);
+
+    }
+    return 0;
+}