301/301

MaskRay · MaskRay · commit c9070e78c79b · 2015-12-19T17:24:18.000+08:00
diff --git a/README.md b/README.md
@@ -2,7 +2,7 @@
 
 [LeetCode solutions](http://maskray.me/blog/2014-06-29-leetcode-solutions) gives some thoughts on selected problems.
 
-Solved 298/298 problems.
+Solved 301/301 problems.
 
 ## Database
 
@@ -12,6 +12,9 @@ See [database.md](database.md)
 
 | # | Title | Solution |
 |---| ----- | -------- |
+|318|[Maximum Product of Word Lengths](https://leetcode.com/problems/maximum-product-of-word-lengths/)|[maximum-product-of-word-lengths.cc](maximum-product-of-word-lengths.cc)|
+|317|[Shortest Distance from All Buildings](https://leetcode.com/problems/shortest-distance-from-all-buildings/)|[shortest-distance-from-all-buildings.cc](shortest-distance-from-all-buildings.cc)|
+|316|[Remove Duplicate Letters](https://leetcode.com/problems/remove-duplicate-letters/)|[remove-duplicate-letters.cc](remove-duplicate-letters.cc)|
 |315|[Count of Smaller Numbers After Self](https://leetcode.com/problems/count-of-smaller-numbers-after-self/)|[count-of-smaller-numbers-after-self.cc](count-of-smaller-numbers-after-self.cc)|
 |314|[Binary Tree Vertical Order Traversal](https://leetcode.com/problems/binary-tree-vertical-order-traversal/)|[binary-tree-vertical-order-traversal.cc](binary-tree-vertical-order-traversal.cc)|
 |313|[Super Ugly Number](https://leetcode.com/problems/super-ugly-number/)|[super-ugly-number.cc](super-ugly-number.cc)|
diff --git a/maximum-product-of-word-lengths.cc b/maximum-product-of-word-lengths.cc
@@ -0,0 +1,21 @@
+// Maximum Product of Word Lengths
+class Solution {
+public:
+  int maxProduct(vector<string>& words) {
+    vector<int> a;
+    int r = 0;
+    for (auto &w: words) {
+      int m = 0;
+      for (auto c: w)
+        m |= 1 << c-'a';
+      int i = 0;
+      for (auto mm: a) {
+        if (! (m & mm))
+          r = max(r, int(w.size() * words[i].size()));
+        i++;
+      }
+      a.push_back(m);
+    }
+    return r;
+  }
+};
diff --git a/remove-duplicate-letters.cc b/remove-duplicate-letters.cc
@@ -0,0 +1,23 @@
+// Remove Duplicate Letters
+#define REP(i, n) for (int i = 0; i < (n); i++)
+
+class Solution {
+public:
+  string removeDuplicateLetters(string s) {
+    int n = s.size(), last[26] = {};
+    bool in[26] = {};
+    string r;
+    REP(i, n)
+      last[s[i]-'a'] = i;
+    REP(i, n)
+      if (! in[s[i]-'a']) {
+        while (r.size() && s[i] < r.back() && i < last[r.back()-'a']) {
+          in[r.back()-'a'] = false;
+          r.pop_back();
+        }
+        in[s[i]-'a'] = true;
+        r.push_back(s[i]);
+      }
+    return r;
+  }
+};
diff --git a/shortest-distance-from-all-buildings.cc b/shortest-distance-from-all-buildings.cc
@@ -0,0 +1,41 @@
+// Shortest Distance from All Buildings
+typedef pair<int, int> pii;
+#define REP(i, n) for (int i = 0; i < (n); i++)
+
+class Solution {
+public:
+  int shortestDistance(vector<vector<int>>& grid) {
+    int m = grid.size(), n = grid[0].size(), ans = INT_MAX;
+    vector<vector<int>> ds(m, vector<int>(n, 0)), d(m, vector<int>(n));
+    REP(i, m)
+      REP(j, n)
+        if (grid[i][j] == 1) {
+          queue<pii> q;
+          q.emplace(i, j);
+          REP(ii, m)
+            fill_n(d[ii].begin(), n, -1);
+          d[i][j] = 0;
+          while (! q.empty()) {
+            int x, y;
+            tie(x, y) = q.front();
+            q.pop();
+            if (! grid[x][y] || x == i && y == j)
+              REP(k, 4) {
+                int xx = x+((int[]){-1,0,1,0})[k], yy = y+((int[]){0,1,0,-1})[k];
+                if (unsigned(xx) < m && unsigned(yy) < n && d[xx][yy] < 0) {
+                  d[xx][yy] = d[x][y]+1;
+                  q.emplace(xx, yy);
+                }
+              }
+          }
+          REP(ii, m)
+            REP(jj, n)
+              ds[ii][jj] = ds[ii][jj] < 0 || d[ii][jj] < 0 ? -1 : ds[ii][jj]+d[ii][jj];
+        }
+    REP(i, m)
+      REP(j, n)
+        if (! grid[i][j] && ds[i][j] >= 0)
+          ans = min(ans, ds[i][j]);
+    return ans == INT_MAX ? -1 : ans;
+  }
+};
