cryptarithm.c

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#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <math.h>

int main(void)
{
    for (int x = 10000; x <= 99999; ++x){
        int roads=1;
        int cross = x;
        int danger=1;
        int c = cross / 10000;
        int bits1 = 1 << c;
        int r = (cross / 1000) % 10;            
        if (r == 0)
            continue;
        if (( bits1 >> r) % 2)
            continue;
        bits1 +=  1 << r;
        int o= (cross%1000)/100;
        if (( bits1 >> o) % 2)
            continue;
        bits1 +=  1 << o;
        int s= cross%10;
        if (( bits1 >> s) % 2)
            continue;
        bits1 +=  1 << s;
        int s2=cross/10%10;
        if(s2!=s)
            continue;
        for (int y = 1; y <= 99; ++y){
            int bits2=bits1;
            int ad = y;
            int a= ad/10;
            if (( bits2 >> a) % 2)
                continue;
            bits2 +=  1 << a;
            int d= ad%10;
            if(d==0)
                continue;
            if (( bits2 >> d) % 2)
                continue;
            bits2 +=  1 << d;
            roads=s+(ad*10)+o*1000+r*10000;
            for(int z=1;z<=999;++z){
                int bits3=bits2;
                int nge=z;
                int n= nge/100;
                if (( bits3 >> n) % 2)
                    continue;
                bits3 +=  1 << n;
                int g= (nge/10)%10;
                if (( bits3 >> g) % 2)
                    continue;
                bits3 +=  1 << g;
                int e= nge%10;
                if (( bits3 >> e) % 2)
                    continue;
                bits3 +=  1 << e;
                danger=r+nge*10+a*10000+d*100000;
                int result;
                result =roads+cross;
                if (danger==result)
                    printf("cross=%d, roads=%d and  danger=%d is a solution\n",cross,roads,danger);
            }
            
        }
    }   
    return EXIT_SUCCESS;
}