Create 1189_xiaoxiaoluo.cpp

From http://blog.csdn.net/xiaoxiaoluo/article/details/7338863

POJ/1189_xiaoxiaoluo.cpp

@@ -0,0 +1,66 @@
+#include <iostream>
+#include <cstdio>
+#include <cmath>
+
+using namespace std;
+int const maxn = 51 + 51 * 50 / 2;
+int n, m;
+long long dp[55][55];
+bool triangle[maxn];
+
+long long gcd(long long a, long long b)
+{
+    if(b)
+        return gcd(b, a % b);
+    return a;
+}
+
+int main()
+{
+    scanf("%d %d", &n, &m);
+    char s[5];
+    int index = 1;
+    for(int i = 1; i <= n; i++)
+    {
+        for(int j = 1; j <= i; j++)
+        {
+            scanf("%s", s);
+            if(s[0] == '*')
+                triangle[index++] = true;
+            else
+                triangle[index++] = false;
+        }
+    }
+    dp[1][1] = 1;
+    for(int i = 1; i <= n; i++)
+        dp[1][1] <<= 1;
+    for(int i = 1; i <= n; i++)
+    {
+        int id = i * (i - 1) / 2;
+        for(int j = 1; j <= i; j++)
+        {
+            if(triangle[id + j])
+            {
+                dp[i+1][j] += dp[i][j] >> 1;
+                dp[i+1][j+1] += dp[i][j] >> 1;
+            }
+            else
+            {
+                dp[i+2][j+1] += dp[i][j];
+            }
+        }
+    }
+    long long ans1 = dp[n+1][m+1];
+    long long ans2 = 0;
+    for(int i = 1; i <= n + 1; i++)
+        ans2 += dp[n+1][i];
+
+    long long k = gcd(ans1,ans2);
+    if(ans1 == 0)
+    {
+        ans2 = 1;
+        k = 1;
+    }
+    printf("%lld/%lld\n", ans1 / k, ans2 / k);
+
+}