coderloop: src/collatz.c annotate

initial committ

rev	line source
rlm@0	1
rlm@0	2 #include <stdio.h>
rlm@0	3 #include <stdlib.h>
rlm@0	4
rlm@0	5 int main(int argc, char *argv[]){
rlm@0	6 FILE *fp;
rlm@0	7 int n;
rlm@0	8 if((fp=fopen(argv[1] ,"r")) == NULL) {
rlm@0	9 printf("Cannot open file.\n");
rlm@0	10 exit(1);}
rlm@0	11 fscanf(fp, "%d", &n); /* read from file */
rlm@0	12 int answer = search_collatz(n);
rlm@0	13 printf("%d\n", answer); }
rlm@0	14
rlm@0	15 long long collatz_next(long long n){
rlm@0	16 if (!(n % 2)){
rlm@0	17 return n/2;}
rlm@0	18 else {
rlm@0	19 return 1+(n*3);}}
rlm@0	20
rlm@0	21 int collatz_length(int n){
rlm@0	22 long long t = n;
rlm@0	23 int d = 1;
rlm@0	24 while (t > 1){
rlm@0	25 t = collatz_next(t);
rlm@0	26 d++;}
rlm@0	27 return d;}
rlm@0	28
rlm@0	29 int search_collatz(int n){
rlm@0	30 int max = 0;
rlm@0	31 int max_val = 0;
rlm@0	32 int temp_val;
rlm@0	33 int i;
rlm@0	34 for (i = 1; i<n; i++){
rlm@0	35 temp_val = collatz_length(i);
rlm@0	36 if (temp_val > max_val){
rlm@0	37 max = i;
rlm@0	38 max_val = temp_val;}}
rlm@0	39 return max;}
rlm@0	40

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