C++实现Bellmanford算法

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#include<iostream>#include<cctype>#include<sstream>#include<string>#include<algorithm>#include<map>#include<cstring>#include<cstdio>#include<iomanip>#include<vector>#include<queue>using namespace std;const int INF = 100000000;struct Node{int dist;int pre;Node() : dist(INF), pre(-1) {}};int main(void) {cout << "Bellmanford Algorithm for Directed Acyclic Graph: " << endl;while (true) {int nNodes;cout << "Number of Nodes: ";cin >> nNodes;vector<vector<int> > Wgt(nNodes, vector<int>(nNodes, INF));for (int i = 0; i < nNodes; ++i)Wgt[i][i] = 0;int nEdges;cout << "Number of Edges: ";cin >> nEdges;cout << "Src  Dest  Dist(< " << INF << "): " << endl;for (int i = 0; i < nEdges; ++i) {int src, dest, dist;cout << "[" << i << "]: ";cin >> src >> dest >> dist;Wgt[src][dest] = dist;}for (int i = 0; i < nNodes; ++i) {for (int j = 0; j < nNodes; ++j) {if (Wgt[i][j] != INF)cout << " " << setw(3) << Wgt[i][j];elsecout << " " << "INF";}cout << endl;}//Bellmanford//INITIALIZE_SINGLE_SOURCEvector<Node> Rec(nNodes);Rec[0].dist = 0;//RELAXfor (int k = 0; k < nNodes - 1; ++k)//nNodes steps.for (int i = 0; i < nNodes; ++i) {for (int j = 0; j < nNodes; ++j) {if (Wgt[i][j] != INF)if (Rec[j].dist > Wgt[i][j] + Rec[i].dist) {Rec[j].dist = Wgt[i][j] + Rec[i].dist;Rec[j].pre = i;}}}//CHECK_WEIGHTfor (int i = 0; i < nNodes; ++i) {for (int j = 0; j < nNodes; ++j) {\if (Wgt[i][j] != INF)if (Rec[j].dist > Wgt[i][j] + Rec[i].dist) {cout << "Negative weight circut." << endl;}}}for (int i = 0; i < nNodes; ++i) {cout << "[" << i << "]  Dist: " << Rec[i].dist << ", Pre: " << Rec[i].pre << endl;}}return 0;}
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