Added Problem 158 B

codeforces/taxi/Makefile

@@ -0,0 +1,13 @@
+CXX := g++
+CXXFLAGS := -std=c++14 -Wall -o out
+
+default: out run
+
+out: main.cpp
+	$(CXX) $(CXXFLAGS) main.cpp
+
+clean:
+	$(RM) out
+
+run:
+	./out

codeforces/taxi/README.md

@@ -0,0 +1,3 @@
+# README
+
+[http://codeforces.com/problemset/problem/158/B](http://codeforces.com/problemset/problem/158/B)

codeforces/taxi/main.cpp

@@ -0,0 +1,44 @@
+
+#include<bits/stdc++.h>
+using namespace std;
+typedef long long int INT;
+
+int main()
+{
+    int n;
+    cin>>n;
+    int a[4]={0};
+    int x;
+    for(int i=0;i<n;i++)
+        {
+        cin>>x;
+        a[x-1]++;
+        /*
+        Maps number of groups of 1 -> a[0]
+             number of groups of 2 -> a[1]
+             number of groups of 3 -> a[2]
+             number of groups of 4 -> a[3]
+        */
+    }
+    int group4=a[3];
+    int group3_1=min(a[2],a[0]);
+    int left_3=a[2]-group3_1;
+    int left_1=a[0]-group3_1;
+    int group2_2=a[1]/2;
+    int left_2=a[1]%2;
+    int group2_1_1=left_2;
+    if(group2_1_1 && left_2)
+    {
+        if(left_1>=2)
+        {
+            left_1-=2;
+        }
+        else if(left_1>=1)
+        {
+            left_1-=1;
+        }
+    }
+    int group1=ceil(left_1/4.0);
+    int ans=group4 + group3_1 + group2_2 + left_3 + group2_1_1 + group1;
+    cout<<ans;
+}