612 - DNA Sorting

https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=553

Author: david-perez

UVa/000612.cpp

@@ -0,0 +1,59 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+int n;
+
+int inv(string &s, int i, int j) {
+    if (j <= i) return 0;
+
+    int mid = (i + j) / 2;
+    int invl = inv(s, i, mid);
+    int invr = inv(s, mid+1, j);
+
+    string t;
+    int invm = 0;
+    int u = i, v = mid+1;
+    while (u <= mid && v <= j) {
+        if (s[u] <= s[v]) t += s[u++];
+        else {
+            invm += mid - u + 1;
+            t += s[v++];
+        }
+    }
+
+    while (u <= mid) t += s[u++];
+    while (v <= j) t += s[v++];
+
+    for (int k = i; k <= j; k++) s[k] = t[k-i];
+    
+    return invl + invr + invm;
+}
+
+bool cmp(string s, string t) {
+    return inv(s, 0, n-1) < inv(t, 0, n-1);
+}
+
+int main() {
+    int M;
+    cin >> M;
+    while (M--) {
+        int m;
+        cin >> n >> m;
+        vector<string> v;
+        while (m--) {
+            string s;
+            cin >> s;
+            v.push_back(s);
+        }
+
+        stable_sort(v.begin(), v.end(), cmp);
+        for (string &s : v) cout << s << endl;
+
+        if (M > 0) cout << endl;
+    }
+
+    return 0;
+}