We use cookies to ensure you have the best browsing experience on our website. Please read our cookie policy for more information about how we use cookies.
  1. All Contests
  2. ProjectEuler+
  3. Project Euler #179: Consecutive positive divisors
  4. Discussions

Project Euler #179: Consecutive positive divisors

Sort by

recency

|

62 Discussions

|

  • tkloszewski
     + 0 comments

    First time I couldn't pass tests because of using single System.out.println and Scanner classes. After swicthing to BufferedWriter and BufferedReader all test cases passed.

  • urossevkusic
     + 0 comments

    C solution based on an idea from this blog. For some reason, the same idea failed on C++ due to timeout.

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

int main() {
    
    unsigned t;
    scanf("%u", &t);
    
    // divisors sieve
    unsigned N = 1e7;
    unsigned *sieve, *pref_sum;
    sieve = (unsigned *) calloc(N + 1, sizeof(unsigned));
    pref_sum = (unsigned *) calloc(N + 1, sizeof(unsigned));
    
    for(unsigned i = 1; i <= N; ++i)
        for(unsigned j = i; j <= N; j += i)
            ++sieve[j];
    
    for(unsigned i = 3; i <= N; ++i)
        pref_sum[i] = pref_sum[i - 1] + (sieve[i] == sieve[i - 1]);
    
    for(unsigned i = 0; i < t; ++i) {
        unsigned k;
        scanf("%u", &k);
        
        printf("%u\n", pref_sum[k]);
    }
    
    free(sieve);
     
    return 0;
}

  • APovalyaev
     + 0 comments

    Can anybody tell me what I'm missing?

    # Enter your code here. Read input from STDIN. Print output to STDOUT
t = int(input().rstrip())
nums = [0]*(10**6)
col = [0]*(10**6)
max_nums = 1
nums[0] = 1

def enlarge_max(next_max):
    global max_nums
    global nums
    global col
    
    #nums[0] = 1
    #print("enlarging from {} to {}".format(max_nums, next_max))
    for i in range(1, next_max+1):
        ss = int(max_nums / i) * i
        #if ss == max_nums:
        #    nums[ss-1] += 1
        ss += i
        #print("... i={} starting ss={}".format(i, ss))
        while ss <= next_max:
            #print("   cur ss={}".format(ss))
            nums[ss-1] += 1
            ss += i
            
    #print("cur nums={}".format(nums[0:next_max]))
    #print("new max = {}".format(next_max))
    prev_col = col[max_nums-1]
    #print("    prev max = {} prev_col = {}".format(max_nums, prev_col))
    
            
    for i in range(max_nums, next_max):
        #col[i-1] = prev_col
        
        if nums[i] == nums[i+1]:
            #print("  found equality at i={} {}={}".format(i, nums[i], nums[i+1]))
            prev_col += 1
        col[i] = prev_col
    
    #print(" arr equality={}".format(col[0:next_max]))
            
            
    max_nums = next_max
        
for _ in range(0, t):
    k = int(input().rstrip())
    enlarge_max(k)
    print("{}".format(col[k-1]))

  • vgshyam18
     + 0 comments

    What is actully n? explaination is too short to understand the output. The only n < 15 are 2 and 14.

  • avjtndy
     + 0 comments

    Can anyone tell me what am I missing?? I am able to pass test case 0 not rest of them . Please help thank you

    con <- file("stdin", open = "r")
data <- as.numeric(readLines(con))

for (i in 1:data[1]){
    I <- data[i+1]
    n <- array(0,dim = I)
for (i in 1:floor((I-1)/2)){
  for (j in seq(i*2,I, by = i)){
    n[j]= n[j]+1
  } 
 }
 b <- 0
 for(i in 2:I){
  if((n[i]==n[i-1])==TRUE){
    b <- b+1
  }
 }
     cat(b,sep = "\n")
}