Weekly Contest 134

Author: MaskRay

coloring-a-border.cc

@@ -0,0 +1,25 @@
+// Coloring A Border
+class Solution {
+public:
+  vector<vector<int>> colorBorder(vector<vector<int>>& a, int r, int c, int color) {
+    int n = a.size(), m = a[0].size(), aa = a[r][c];
+    vector<vector<char>> v(n, vector<char>(m));
+    vector<pair<int,int>> q;
+    q.emplace_back(r, c);
+    v[r][c] = 1;
+    for (int i = 0; i < q.size(); i++) {
+      tie(r, c) = q[i];
+      if (r && a[r-1][c] == aa && !v[r-1][c]++) q.emplace_back(r-1,c);
+      if (r+1<n && a[r+1][c] == aa && !v[r+1][c]++) q.emplace_back(r+1,c);
+      if (c && a[r][c-1] == aa && !v[r][c-1]++) q.emplace_back(r,c-1);
+      if (c+1<m && a[r][c+1] == aa && !v[r][c+1]++) q.emplace_back(r,c+1);
+    }
+    for (auto &x: q) {
+      tie(r, c) = x;
+      if (!r || !v[r-1][c] || r+1==n || !v[r+1][c] ||
+         !c || !v[r][c-1] || c+1==m || !v[r][c+1])
+        a[r][c] = color;
+    }
+    return a;
+  }
+};

escape-a-large-maze.cc

@@ -0,0 +1,22 @@
+// Escape a Large Maze
+class Solution {
+public:
+  bool isEscapePossible(vector<vector<int>>& bs, vector<int>& src, vector<int>& dst) {
+    const long N = 1000001;
+    unordered_set<long> v;
+    for (auto &b: bs)
+      v.insert(b[0]*N+b[1]);
+    vector<pair<int,int>> q{{src[0], src[1]}};
+    v.insert(src[0]*N+src[1]);
+    for (int i=0; i<q.size(); i++) {
+      int x, y;
+      tie(x, y) = q[i];
+      if (i == 200*200 || x == dst[0] && y == dst[1]) return true;
+      if (x && v.insert((x-1)*N+y).second) q.emplace_back(x-1, y);
+      if (x+1<N-1 && v.insert((x+1)*N+y).second) q.emplace_back(x+1, y);
+      if (y && v.insert(x*N+y-1).second) q.emplace_back(x, y-1);
+      if (y+1<N-1 && v.insert(x*N+y+1).second) q.emplace_back(x, y+1);
+    }
+    return false;
+  }
+};

moving-stones-until-consecutive.cc

@@ -0,0 +1,13 @@
+// Moving Stones Until Consecutive
+class Solution {
+public:
+  vector<int> numMovesStones(int a, int b, int c) {
+    if (a>b) swap(a,b);
+    if (b>c) swap(b,c);
+    if (a>b) swap(a,b);
+    vector<int> r;
+    r.push_back(a+1==b&&b+1==c ? 0 : a+2>=b||b+2>=c ? 1 : 2);
+    r.push_back(c-a-2);
+    return r;
+  }
+};

uncrossed-lines.cc

@@ -0,0 +1,24 @@
+// Uncrossed Lines
+#define FOR(i, a, b) for (remove_cv<remove_reference<decltype(b)>::type>::type i = (a); i < (b); i++)
+#define REP(i, n) FOR(i, 0, n)
+#define ROF(i, a, b) for (remove_cv<remove_reference<decltype(b)>::type>::type i = (b); --i >= (a); )
+
+class Solution {
+public:
+  int maxUncrossedLines(vector<int>& A, vector<int>& B) {
+    int n = A.size(), m = B.size();
+    vector<vector<int>> s(n+1, vector<int>(m+1));
+    REP(i, n)
+      REP(j, m) {
+        int ss = 0;
+        REP(k, j+1)
+          if (A[i]==B[k])
+            ss = max(ss, s[i][k]+1);
+        REP(k, i+1)
+          if (A[k]==B[j])
+            ss = max(ss, s[k][j]+1);
+        s[i+1][j+1] = max(s[i+1][j],max(s[i][j+1],ss));
+      }
+    return s[n][m];
+  }
+};