UVa 11307

用dp(u,v)表示在u点涂颜色为v的和的最小值，则状态转移方程为

dp(u,v) = v + min{dp(m, vi1), dp(m,vi2),...}，u->m存在边, vi表示在m点上可涂的颜色值。

代码如下：

#include <iostream>#include <fstream>#include <vector>#include <string>#include <cstring>#include <sstream>#include <cstdlib>#include <algorithm>#include <climits>using namespace std;class Solution{public:void init(){memset(dp, 0x00, sizeof(dp));memset(p, 0xff, sizeof(p));for (int i = 0; i < N; i++){adjList[i].clear();}}void setn(int n){this->n = n;}void addEdge(vector<int> v){if (v.size() > 1){for (size_t i = 1; i < v.size(); i++){adjList[v[0]].push_back(v[i]);p[v[i]] = v[0];}}}int solve(){int root = findRoot();//cout << "root:" << root << endl;int ans = INT_MAX;for (int i = 0; i < MAXCOLOR; i++){ans = min(ans, dynamicProgram(root, i + 1));}return ans;}private:int findRoot(){for (int i = 0; i < n; i++){if (p[i] == -1) return i;}return -1;}int dynamicProgram(int u, int v){if (dp[u][v - 1]) return dp[u][v - 1];int& ans = dp[u][v - 1];ans = v;for (size_t i = 0; i < adjList[u].size(); i++){int res = INT_MAX;for (int j = 0; j < MAXCOLOR; j++){if (j + 1 == v) continue;int tmp = dynamicProgram(adjList[u][i], j + 1);res = min(res, tmp);}ans += res;}return ans;}private:static const int N = 10001;static const int MAXCOLOR = 6;int dp[N][MAXCOLOR];int n;vector<int> adjList[N];int p[N];};Solution solution;vector<int> sepstr(char *str, char *sep){char *tok = strtok(str, sep);vector<int> ans;while (tok){int v = atoi(tok);ans.push_back(v);tok = strtok(NULL, sep);}return ans;}int main(){#ifndef ONLINE_JUDGEifstream fin("f:\\OJ\\uva_in.txt");streambuf* back = std::cin.rdbuf(fin.rdbuf());#endifint n;while (cin >> n){if (n == 0) break;solution.init();solution.setn(n);string s;getline(cin, s);for (int i = 0; i < n; i++){getline(cin, s);vector<int> v = sepstr(const_cast<char*>(s.c_str()), ": ");solution.addEdge(v);}int res = solution.solve();cout << res << endl;}#ifndef ONLINE_JUDGEcin.rdbuf(back);#endifreturn 0;}