leetcode

daiwb · daiwb · commit 44f43634a4d7 · 2013-10-11T15:43:05.000-07:00
diff --git a/LeetCode/fourSum.cpp b/LeetCode/fourSum.cpp
@@ -0,0 +1,64 @@
+#include <iostream>
+#include <climits>
+#include <algorithm>
+#include <string>
+#include <cstring>
+#include <vector>
+using namespace std;
+
+#define REP(i,n) for(int i=0;i<(n);++i)
+#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
+#define RFOR(i,a,b) for(int i=(a);i>=(b);--i)
+typedef long long LL;
+
+class Solution {
+public:
+    vector<vector<int> > fourSum(vector<int> &num, int target) {
+        sort(num.begin(), num.end());
+        vector<vector<int> > ret;
+        int n = num.size();
+        REP(i,n) {
+            if (i != 0 && num[i] == num[i - 1]) continue;
+            FOR(j,i+1,n-1) {
+                if (j != i + 1 && num[j] == num[j - 1]) continue;
+                int s = num[i] + num[j];
+                int lt = j + 1;
+                int rt = n - 1;
+                while (lt < rt) {
+                    if (num[lt] + num[rt] + s == target) {
+                        vector<int> tmp;
+                        tmp.push_back(num[i]);
+                        tmp.push_back(num[j]);
+                        tmp.push_back(num[lt]);
+                        tmp.push_back(num[rt]);
+                        ret.push_back(tmp);
+                        ++lt;
+                        --rt;
+                    } else if (num[lt] + num[rt] + s < target) {
+                        ++lt;
+                    } else {
+                        --rt;
+                    }
+                }
+            }
+        }
+        ret.erase(unique(ret.begin(), ret.end()), ret.end());
+        return ret;
+    }
+};
+
+int main() {
+    Solution s = Solution();
+    int data[] = {1, 0, -1, 0, -2, 2};
+    vector<int> mm;
+    int sz = sizeof(data) / sizeof(int);
+    REP(i,sz) mm.push_back(data[i]);
+    vector<vector<int> > ret = s.fourSum(mm, 0);
+    REP(i,ret.size()) {
+        REP(j,ret[i].size()) {
+            cout << ret[i][j] << " ";
+        }
+        cout << endl;
+    }
+    return 0;
+}
diff --git a/LeetCode/letterCombinations.cpp b/LeetCode/letterCombinations.cpp
@@ -0,0 +1,61 @@
+#include <iostream>
+#include <climits>
+#include <algorithm>
+#include <string>
+#include <cstring>
+#include <vector>
+#include <map>
+using namespace std;
+
+#define REP(i,n) for(int i=0;i<(n);++i)
+#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
+#define RFOR(i,a,b) for(int i=(a);i>=(b);--i)
+typedef long long LL;
+
+class Solution {
+public:
+    string str, s;
+    int len;
+    vector<string> ret;
+    map<char, string> mp;
+
+    void dfs(int idx) {
+        if (idx == len) {
+            ret.push_back(s);
+            return;
+        }
+
+        string t = mp[str[idx]];
+        REP(i,t.length()) {
+            s[idx] = t[i];
+            dfs(idx + 1);
+        }
+    }
+    
+    vector<string> letterCombinations(string digits) {
+        mp['0'] = "0";
+        mp['1'] = "1";
+        mp['2'] = "abc";
+        mp['3'] = "def";
+        mp['4'] = "ghi";
+        mp['5'] = "jkl";
+        mp['6'] = "mno";
+        mp['7'] = "pqrs";
+        mp['8'] = "tuv";
+        mp['9'] = "wxyz";
+        s = str = digits;
+        len = str.length();
+        ret.clear();
+        dfs(0);
+        return ret;
+    }
+};
+
+int main() {
+    Solution s = Solution();
+    vector<string> mm = s.letterCombinations("23");
+    REP(i,mm.size()) {
+        cout << mm[i] << endl;
+    }
+    return 0;
+}
diff --git a/LeetCode/threeSumClosest.cpp b/LeetCode/threeSumClosest.cpp
@@ -0,0 +1,52 @@
+#include <iostream>
+#include <climits>
+#include <algorithm>
+#include <string>
+#include <cstring>
+#include <vector>
+using namespace std;
+
+#define REP(i,n) for(int i=0;i<(n);++i)
+#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
+#define RFOR(i,a,b) for(int i=(a);i>=(b);--i)
+typedef long long LL;
+
+class Solution {
+public:
+    int threeSumClosest(vector<int> &num, int target) {
+        sort(num.begin(), num.end());
+        int ret = num[0] + num[1] + num[2];
+        int d = abs(ret - target);
+        int n = num.size();
+        REP(i,n) {
+            if (i != 0 && num[i] == num[i - 1]) continue;
+            int lt = i + 1;
+            int rt = n - 1;
+            while (lt < rt) {
+                int s = num[i] + num[lt] + num[rt];
+                if (s == target) {
+                    return s;
+                } else {
+                    if (abs(s - target) < d) {
+                        ret = s;
+                        d = abs(s - target);
+                    }
+                    if (s < target) ++lt;
+                    else --rt;
+                }
+            }
+        }
+        return ret;
+    }
+};
+
+int main() {
+    Solution s = Solution();
+    int data[] = {-1, 2, 1, -4};
+    vector<int> mm;
+    int sz = sizeof(data) / sizeof(int);
+    REP(i,sz) mm.push_back(data[i]);
+    int ret = s.threeSumClosest(mm, 1);
+    cout << ret << endl;
+    return 0;
+}
