Travel business Issues

NPC problem, there is no polynomial-time algorithm, but in the algorithm can be done pruning optimization:

1. First write algorithm, missing pruning: The shortest path calculated before the current path >=, the current path does not continue to traverse

#include <cstdio>#include<iostream>#include<cstring>using namespacestd;intN;intmap[ A][ A];intflag[ A];intSolveintstart) {    intI,val, all_visited =1, Min =999999999;  for(i =2; I <= N; i++) {        if(Flag[i]! =0|| Map[start][i] = =0) {            Continue; } all_visited=0; Flag[i]=1;//visitedval = map[start][i] +solve (i); if(Val <min) {min=Val; } Flag[i]=0; }    if(all_visited) {returnmap[start][1]; } Else {        returnmin; }}intMainintargcChar**argv) {    intTC, T, I, J; //freopen ("Input.txt", "R", stdin);CIN >>T;  for(TC =0; TC < T; Tc++) {cin>>N;  for(i =1; I <= N; i++) {             for(j =1; J <= N; J + +) {cin>>Map[i][j]; }} memset (flag,0x00, A*sizeof(int)); printf ("%d\n", Solve (1)); }    return 0;}

2. Optimization algorithm, PATH determination pruning

#include <cstdio>#include<iostream>#include<cstring>using namespacestd;intN, cost, min_cost;intmap[ -][ -];intflag[ -];intsum;voidSolveintstart) {    inti; if(Sum >=N) {if(map[start][1]!=0&& Cost + map[start][1] <min_cost) {Min_cost= Cost + map[start][1]; }        return; }     for(i =2; I <= N; i++) {        if(Flag[i]! =0|| Map[start][i] = =0|| Cost + map[start][i] >=min_cost) {            Continue; } Flag[i]=1;//visitedCost + =Map[start][i]; Sum++;        Solve (i); Sum--; Flag[i]=0; Cost-=Map[start][i]; }}intMainintargcChar**argv) {    intTC, T, I, J; //freopen ("Input.txt", "R", stdin);CIN >>T;  for(TC =0; TC < T; Tc++) {cin>>N;  for(i =1; I <= N; i++) {             for(j =1; J <= N; J + +) {cin>>Map[i][j]; }} memset (flag,0x00, -*sizeof(int)); Cost=0; Min_cost =99999999999; Sum=1; Solve (1); cout<<min_cost<<Endl; }    return 0;}

Notice the red code, don't miss it.

Travel business Issues