graph, tdp

Author: tjd229

TopCoder/TreeAndCycle_tdp.cpp

@@ -0,0 +1,54 @@
+//category : graph, tdp
+#include <vector>
+#include <algorithm>
+#include <stdio.h>
+using namespace std;
+
+class TreeAndCycle{
+public:
+   int n;
+   int d[100][3];  //degree
+   int cut[100];
+   vector<int> *costV;
+
+   vector<int> edge[100];
+   void dfs(int ix){
+      int i, j, k;
+      int t[3];
+      d[ix][0] = 0;
+      for (i = 0; i < edge[ix].size(); i++){
+         int to = edge[ix][i];
+         dfs(to);
+         t[0] = t[1] = t[2] = 1e9;
+         for (j = 0; j < 3; j++){
+            for (k = 0; k < 3; k++){
+               t[j] = min(t[j], d[ix][j] + d[to][k] + cut[to]);
+               if (j > 1 || k > 1) continue;
+               t[j + 1] = min(t[j + 1], d[ix][j] + d[to][k] - costV->at(to));               
+            }
+         }
+         for (j = 0; j < 3; j++) d[ix][j] = t[j];
+      }
+      d[ix][0] += costV->at(ix);
+      d[ix][0] += costV->at(ix);
+      if (edge[ix].size())
+         d[ix][1] += costV->at(ix);
+      //printf("%d:%d,%d,%d\n", ix, d[ix][0], d[ix][1], d[ix][2]);
+   }
+   
+   
+   int minimize(vector<int> costV, vector<int> pre, vector<int> costE){
+      int i;
+      n = costV.size();
+      this->costV = &costV;
+      for (i = 0; i < n - 1; i++){
+         edge[pre[i]].push_back(i + 1);
+         cut[i + 1] = costE[i];
+         d[i][0] = d[i][1]= d[i][2]= 1e9;
+      }
+      d[i][0] = d[i][1] = d[i][2] = 1e9;
+      dfs(0);
+
+      return min(d[0][1], min(d[0][0],d[0][2]));
+   }
+};