IN Danger walk

DANGER.cpp

@@ -0,0 +1,49 @@
+//DATE: 14/10/2015
+//Author: Ramjeet Saran
+//http://www.spoj.com/problems/DANGER/
+
+# include <bits/stdc++.h>
+# include <cmath>
+# define gc getchar_unlocked
+# define pc putchar_unlocked
+# define RWTYPE long int
+
+using namespace std;
+
+RWTYPE fastwrite(RWTYPE inp) {
+  RWTYPE a = (inp < 0) ? -inp : inp;
+  char snum[20];
+  int i = 0;
+  do
+  {
+    snum[i++] = a % 10 + 48;
+    a = a / 10;
+  }while(a != 0);
+
+  if(inp < 0)
+    snum[i++] = '-';
+  i--;
+
+  while(i >= 0)
+    pc(snum[i--]);
+  pc('\n');
+}
+
+int main(){
+  string in;
+  double n;
+  int _log, ans;
+  cin>>in;
+  while(1){
+    if(in[0] == '0' && in[1] == '0' && in[3] == '0')
+      break;
+    n = (in[0] - '0') * 10 + (in[1] - '0');
+    n *= pow(10, in[3] - '0');
+   // cout<<n<<endl;
+    _log = log2(n);
+    //cout<<_log<<endl;
+    ans = (n - (1 << _log)) * 2 + 1;
+    cout<<ans<<endl;
+    cin>>in;
+  }
+}

Readme

@@ -83,3 +83,4 @@ http://www.spoj.com/users/raj94/
 79) ABCDEF
 80) GLJIVE
 81) CPRMT
+82) DANGER