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874天前#include <math.h> |
#include <time.h> |
#include <stdio.h> |
#include <stdlib.h> |
#define NOT_FOUND -1 |
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int get_rand(int upbound) { |
//srand(time(0)); //srand=stdlib.h; time=time.h |
return (int)(ceil(rand()%upbound)); //ceil=math.h; rand=stdlib.h |
} |
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int get_runtime() { |
return clock(); //time=time.h |
} |
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int linear_search(int arr[], int len, int key) { //continuing finding |
int j=-1; int i; |
for (i=0;i<=len-1;i++) if (arr[i]==key) j=i; |
return j; |
} |
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int better_search(int arr[], int len, int key) { //terminating after finding |
int i; |
for (i=len-1;i>=0;i--) if (arr[i]==key) break; |
return i; |
} |
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int sentinel_linear_search(int arr[], int len, int key) { //preventing violation |
int last; |
last=arr[len-1]; |
arr[len-1]=key; |
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int i=0; |
while (arr[i]!=key) i++; |
if (i<(len-1)) return i; |
if (last==key) return len-1; |
else return -1; //check whether is it just the last |
} |
int main() { |
srand(time(0)); |
int a[200000]; |
for (int k=0;k<=190000;k++) { |
a[k+10]=get_rand(10); |
if (k==131072) a[k+10]=22; |
} |
printf("1. get random numbers\n"); |
for (int randi=0;randi<=10;randi++) |
printf("%d\n",get_rand(100)); |
printf("2. LINEAR_SEARCH\n"); |
int time1_S=clock(); |
int result1=linear_search(a,190000,22); |
int time1_E=clock(); |
printf("FOUND_RESULT=%d\n",result1); |
printf("TIME_ELAPSED_MS: %d\n",time1_E-time1_S); |
printf("3. BETTER_SEARCH\n"); |
int time2_S=clock(); |
int result2=better_search(a,190000,22); |
int time2_E=clock(); |
printf("FOUND_RESULT=%d\n",result2); |
printf("TIME_ELAPSED_MS: %d\n",time2_E-time2_S); |
printf("4. SENTINEL_LINEAR_SEARCH\n"); |
int time3_S=clock(); |
int result3=sentinel_linear_search(a,190000,22); |
int time3_E=clock(); |
printf("FOUND_RESULT=%d\n",result3); |
printf("TIME_ELAPSED_MS: %d\n",time3_E-time3_S); |
return 0; |
} |
