Create comb.cpp

ksivaceg · Nov 1, 2020 · 9f5d4d5 · 9f5d4d5
1 parent 4dea701
commit 9f5d4d5
Showing 1 changed file with 27 additions and 0 deletions.
diff --git a/Template/Combination-Number/comb.cpp b/Template/Combination-Number/comb.cpp
@@ -0,0 +1,27 @@
+typedefine long long ll;
+
+main()
+{
+  // compute all C(n,m) saved in comb
+  ll comb[1000][1000];  
+  for (int i = 0; i <= n; ++i) 
+  {
+      comb[i][i] = comb[i][0] = 1;            
+      for (int j = 1; j < i; ++j) 
+      {
+          comb[i][j] = comb[i - 1][j - 1] + C[i - 1][j];
+      }
+  }  
+}
+
+// Compute C(n,m) on demand
+ll help(int n, int m)
+{
+    long long cnt = 1;
+    for(int i = 0; i < m; i++)
+    {
+        cnt *= n - i;
+        cnt /= i + 1;
+    }
+    return cnt;
+}