6.c File Reference

Implementation of the ZigZag Conversion Leetcode problem. More...

#include <assert.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

Include dependency graph for 6.c:

Functions
char *	convert (char *in, uint16_t numRows)
	for assert for unsigned int with fixed size More...
static void	testZigZag (char *s, int numRows, char *expected)
	Self-test implementations. More...
static void	test ()
	Self-test implementations. More...
int	main (void)
	Main function. More...

Detailed Description

Implementation of the ZigZag Conversion Leetcode problem.

A decent solution to the ZigZag conversion problem. Take advantage of the fact that the maximum gap between the chars is 2 times the depth(the number of rows). The actual gap between the two first chars of a rows depends on the depth of the row. The gaps between successives chars on the same row is the complement of the first gap to the maximum gap.

Author

straight_into_the_wall

Function Documentation

convert()

char * convert	(	char *	in,
		uint16_t	numRows
	)

for assert for unsigned int with fixed size

for IO operations for malloc for string tools

Convert a string to the it's zigzag equivalent on a given number of rows.

Parameters

in	the string in input.
numRows	the desired number of rows.

Returns

the converted new (malloced) string.

{
    uint16_t len = strlen(in);
 
    if (len < numRows)
    {
        numRows = len;
    }
    char* out = calloc(len + 1, sizeof(char));
 
    if (numRows < 2)
    {
        memcpy(out, in, len + 1);
        return out;
    }
 
    uint16_t max = numRows - 1;
    uint16_t rr = 2 * max;
    uint16_t i = 0;
    uint16_t o = 0;
    uint16_t delta = 0;
 
    // first row
    while (i < len)
    {
        out[o++] = in[i];
        i += rr;
    }
 
    // middle rows
    for (uint16_t l = 1; l < max; l++)
    {
        i = l;
        delta = 2 * l;
        while (i < len)
        {
            out[o++] = in[i];
            delta = rr - delta;
            i += delta;
        }
    }
 
    // last row
    i = max;
    while (i < len)
    {
        out[o++] = in[i];
        i += rr;
    }
 
    return out;
}

main()

int main

(

void

)

Main function.

Returns

0 on exit

{
    test();  // run self-test implementations
    return 0;
}

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test()

static void test ( void  )

static

Self-test implementations.

Returns

void

{
    char* s01 = "PAYPALISHIRING";
 
    char* r01 = "PINALSIGYAHRPI";
    testZigZag(s01, 4, r01);
 
    char* r02 = "PAHNAPLSIIGYIR";
    testZigZag(s01, 3, r02);
 
    char* s03 = "A";
    testZigZag(s03, 1, s03);
    testZigZag(s03, 3, s03);
 
    char* s04 =
        "cbxdwjccgtdoqiscyspqzvuqivzptlpvooynyapgvswoaosaghrffnxnjyeeltzaiznicc"
        "ozwknwyhzgpqlwfkjqipuu"
        "jvwtxlbznryjdohbvghmyuiggtyqjtmuqinntqmihntkddnalwnmsxsatqqeldacnnpjfe"
        "rmrnyuqnwbjjpdjhdeavkn"
        "ykpoxhxclqqedqavdwzoiorrwwxyrhlsrdgqkduvtmzzczufvtvfioygkvedervvudnegh"
        "bctcbxdxezrzgbpfhzanff"
        "eccbgqfmzjqtlrsppxqiywjobspefujlxnmddurddiyobqfspvcoulcvdrzkmkwlyiqdch"
        "ghrgytzdnobqcvdeqjystm"
        "epxcaniewqmoxkjwpymqorluxedvywhcoghotpusfgiestckrpaigocfufbubiyrrffmwa"
        "eeimidfnnzcphkflpbqsvt"
        "dwludsgaungfzoihbxifoprwcjzsdxngtacw";
 
    char* r04 =
        "cbxdwjccgtdoqiscyspqzvuqivzptlpvooynyapgvswoaosaghrffnxnjyeeltzaiznicc"
        "ozwknwyhzgpqlwfkjqipuu"
        "jvwtxlbznryjdohbvghmyuiggtyqjtmuqinntqmihntkddnalwnmsxsatqqeldacnnpjfe"
        "rmrnyuqnwbjjpdjhdeavkn"
        "ykpoxhxclqqedqavdwzoiorrwwxyrhlsrdgqkduvtmzzczufvtvfioygkvedervvudnegh"
        "bctcbxdxezrzgbpfhzanff"
        "eccbgqfmzjqtlrsppxqiywjobspefujlxnmddurddiyobqfspvcoulcvdrzkmkwlyiqdch"
        "ghrgytzdnobqcvdeqjystm"
        "epxcaniewqmoxkjwpymqorluxedvywhcoghotpusfgiestckrpaigocfufbubiyrrffmwa"
        "eeimidfnnzwccpahtkgfnl"
        "xpdbsqzsjvctwdrwploufdisxgbahuinogzf";
 
    testZigZag(s04, 472, r04);
}

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testZigZag()

static void testZigZag ( char *  s, int  numRows, char *  expected  )

static

Self-test implementations.

Returns

void

{
    char* ret = convert(s, numRows);
    int len = strlen(s);
    int cmp = strncmp(ret, expected, len);
    assert(!cmp);
 
    free(ret);
}

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