Stock Exchange Losses

Easy puzzle, you have a list of values and are looking for the biggest loss possible, i.e the biggest difference between a high value, and a low value which follows it in the list. For this you just have to compute the difference between the current value and the maximum value read yet, and search for the biggest difference.

C

Note the usage of strtok and atoi to read all the integer values contained in a string.

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

int main(int argc, char **argv)
{
    // number of stock values
    int N;
    scanf("%d\n", &N);
    
    /* as each stock value is under 2^31 which is roughly 4*10^9,
       15 chars per value is largely enough*/
    char line[15*N];
    fgets(line,15*N,stdin);
    
    /* currentMax and currentMin will store the local minimum and maximum
       stock values, maxLoss will store the maximum loss found yet */
    int stockValue, maxLoss, currentMax, currentMin;
    maxLoss = currentMax = 0;
    currentMin = INT_MAX;
    
    // Uses strtok to read all the stock values
    char *tok;
    tok = strtok(line," ");
    for (int i = 0 ; i < N ; i++) {
        stockValue = atoi(tok);
        
        if (stockValue > currentMax) {
            if (currentMax-currentMin > maxLoss)
                maxLoss = currentMax-currentMin;
            currentMax = currentMin = stockValue;
        } 
        else if (stockValue < currentMin)
            currentMin = stockValue;
            
        tok = strtok(NULL," ");
    }
    
    if (currentMax-currentMin > maxLoss)
        maxLoss = currentMax-currentMin;
        
    printf("%d\n",-maxLoss);
    return EXIT_SUCCESS;
}