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hamiltonian_path.c
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hamiltonian_path.c
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#include <stdio.h>
#define size 100
#define FIN "hamiltonian_path.in"
int road[size][size], //matrix of roads
stack[size],
level,start_node,
n;//number of nodes
void readRoad();
void readRoadFromFile();
void writeRoad();
void bt();
void init();
void print();
int valid();
int succ();
int sol();
int main() {
//printf("Number of cities -> ");
//scanf("%d",&n);
//readRoad();
readRoadFromFile();
writeRoad();
//start_node = 5;
bt();
return(0);
};
void print() {
int i;
for(i = 1; i <= n; i++) printf("%d ", stack[i]);
printf("%d", start_node);
printf("\n");
};
void init() {
stack[level] = 0;
};
int succ() {
if(stack[level] < n) {
stack[level]++;
return 1;
}
return 0;
};
int valid() {
int i;
if(!road[ stack[level - 1] ][ stack[level] ]) return 0;
else {
for(i = 1; i < level; i++) if(stack[i] == stack[level]) return 0;
return 1;
}
};
int sol() {
return (level == n) && (road[ start_node ][ stack[ level ] ] == 1);
};
void bt() {
int hs, is;
stack[1] = start_node;
level = 2;
init();
while(level > 0) {
hs = 1; is = 0;
while(hs && !is) {
hs = succ();
if(hs) is = valid();
}
if(hs) {
if(sol()) print();
else {level++;init();}
} else level--;
}
};
void writeRoad() {
int i,j;
printf("\nMatrix of roads!\n");
printf("\n-------------------\n");
for(i = 1; i <= n; i++) {
for(j = 1; j <= n; j++) {
printf("%d ", road[i][j]);
}
printf("\n");
}
printf("-------------------\n");
};
void readRoadFromFile() {
int edges, a, b;
freopen(FIN, "r",stdin);
scanf("%d %d %d", &n, &edges, &start_node);
int i;
while(edges--) {
scanf("%d %d", &a, &b);
road[a][b] = 1;
road[b][a] = 1;
}
}
void readRoad() {
int i, j;
for(i = 1; i <= n; i++) {
for(j = 1; j <= i - 1; j++) {
printf("mat[%d][%d] ->", i, j);
scanf("%d", &road[i][j]);
road[j][i] = road[i][j];
}
}
};