urlify.cpp

//https://ide.geeksforgeeks.org/ZfAU84Lcxr

#include <bits/stdc++.h> // Include every standard library 
using namespace std; 

typedef long long LL; 
typedef pair<int, int> pii; 
typedef pair<LL, LL> pll; 
typedef pair<string, string> pss; 
typedef vector<int> vi; 
typedef vector<vi> vvi; 
typedef vector<pii> vii; 
typedef vector<LL> vl; 
typedef vector<vl> vvl; 

double EPS=1e-9; 
int INF=1000000005; 
long long INFF=1000000000000000005LL; 
double PI=acos(-1); 
int dirx[8]={ -1, 0, 0, 1, -1, -1, 1, 1 }; 
int diry[8]={ 0, 1, -1, 0, -1, 1, -1, 1 }; 

#define DEBUG fprintf(stderr, "====TESTING====\n") 
#define VALUE(x) cerr << "The value of " << #x << " is " << x << endl 
#define debug(...) fprintf(stderr, __VA_ARGS__) 
#define FOR(a, b, c) for (int(a)=(b); (a) < (c); ++(a)) 
#define FORN(a, b, c) for (int(a)=(b); (a) <= (c); ++(a)) 
#define FORD(a, b, c) for (int(a)=(b); (a) >= (c); --(a)) 
#define FORSQ(a, b, c) for (int(a)=(b); (a) * (a) <= (c); ++(a)) 
#define FORC(a, b, c) for (char(a)=(b); (a) <= (c); ++(a)) 
#define FOREACH(a, b) for (auto&(a) : (b)) 
#define REP(i, n) FOR(i, 0, n) 
#define REPN(i, n) FORN(i, 1, n) 
#define MAX(a, b) a=max(a, b) 
#define MIN(a, b) a=min(a, b) 
#define SQR(x) ((LL)(x) * (x)) 
#define RESET(a, b) memset(a, b, sizeof(a)) 
#define fi first 
#define se second 
#define mp make_pair 
#define pb push_back 
#define ALL(v) v.begin(), v.end() 
#define ALLA(arr, sz) arr, arr + sz 
#define SIZE(v) (int)v.size() 
#define SORT(v) sort(ALL(v)) 
#define REVERSE(v) reverse(ALL(v)) 
#define SORTA(arr, sz) sort(ALLA(arr, sz)) 
#define REVERSEA(arr, sz) reverse(ALLA(arr, sz)) 
#define PERMUTE next_permutation 
#define TC(t) while (t--) 

void urlify(char *str, int len)
{
    int space_count=0;
    int i=0, j=0;
    FOR(i, 0, len){
        if (str[i] == ' ') {
            space_count++;
        }
    }
    int extendedLen = len + 2 * space_count;
    i = extendedLen - 1;
    FORD(j, len - 1, 0){
        if (str[j] != ' ') {
           str[i--] = str[j];
        } else {
            str[i--] = '0';
            str[i--] = '2';
            str[i--] = '%';
        }
    }
}

int main()
{
    char str[]= "Mr John Smith    ";                       
    cout <<"Actual string:"<<str<<"\n";
    urlify(str, 13);
    cout <<"URLified string:"<<str<<"\n";
    return 0;
}