LeetCode093 Restore IP Addresses

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详细见：leetcode.com/problems/restore-ip-addresses

Java Solution: github

package leetcode;import java.util.Arrays;import java.util.HashSet;import java.util.LinkedList;import java.util.List;/* * Given a string containing only digits,  * restore it by returning all possible valid IP address combinations.For example:Given "25525511135",return ["255.255.11.135", "255.255.111.35"]. (Order does not matter) */public class P093_RestoreIPAddresses {public static void main(String[] args) {//List<String> ans = new Solution2().restoreIpAddresses("25525511135");List<String> ans = new Solution2().restoreIpAddresses("2552552563");//List<String> ans = new Solution2().restoreIpAddresses("255255255255");//List<String> ans = new Solution2().restoreIpAddresses("1231231231");//List<String> ans = new Solution2().restoreIpAddresses("1234");//List<String> ans = new Solution2().restoreIpAddresses("0000");//List<String> ans = new Solution2().restoreIpAddresses("11234");//List<String> ans = new Solution2().restoreIpAddresses("010010");tools.Utils.B_打印List_String(ans);}static class Solution {List<String> ans = new LinkedList<String>();HashSet<String> set = new HashSet<>();int[] cs = null;int[] choice = new int[12];    public List<String> restoreIpAddresses(String s) {    if (s == null || s.length() < 4 || s.length() > 12) {    return ans;    }    cs = new int[s.length()];    for (int i = cs.length - 1; i > -1; i --) {     cs[i] = s.charAt(i) - '0';    }    Arrays.fill(choice, - 1);     int first_not_zero = 0;    while (true) {    if (first_not_zero > 3 || cs[first_not_zero] != 0) {    break;    } else {    first_not_zero ++;    }    }    if (cs.length == 4) {    if (first_not_zero == 4) {    ans.add("0.0.0.0");    return ans;    } else {    ans.add(String.format("%d.%d.%d.%d", cs[0], cs[1], cs[2], cs[3]));    return ans;    }    } else if (first_not_zero == 0) {    choice[0] = cs[0];    choice[11] = cs[cs.length - 1];    search(1, 10, 1, 1, cs.length - 2, 1);    } else {    for (int i = 0; i < first_not_zero * 3; i ++) {    choice[i] = 0;    }    choice[3 * first_not_zero] = cs[first_not_zero];    choice[11] = cs[cs.length - 1];    search(3 * first_not_zero + 1, 10, 3 * first_not_zero + 1, first_not_zero + 1, cs.length - 2, first_not_zero + 1);    }        return ans;    }    // chi,chj : choice的开始和结束index    // csi,csj : cs的开始和结束index    private void search(int chi, int chj, int chk, int csi, int csj, int csk) {    if (chk > chj || csk > csj) {    isLegal();    return;    }    if (csj - csk > chj - chk) {    return;    }    for (int cht = chk; cht <= chj; cht ++) {    choice[cht] = cs[csk];    search(chi, chj, cht + 1, csi, csj, csk + 1);    choice[cht] = -1;    }    }// i从0开始    boolean isLegal() {    int[] parts = new int[4];    int count = 0;    for (int i = 0; i < parts.length; i ++) {    parts[i] = 0;    int index = i * 3;    boolean isAll_blank = true;    int this_count = 0;    for (int j = 0; j < 3; j ++) {    if (choice[index + j] == -1) {    continue;    }    isAll_blank = false;    this_count ++;    count ++;    if (j != 0 && parts[i] == 0 && choice[index + j] != 0) {    return false;    }    parts[i] = parts[i] * 10 + choice[index + j];    }    if (parts[i] == 0 && this_count != 1) {    count -= (this_count - 1);    }    if (isAll_blank) {    return false;    }    if (parts[i] < 0 || parts[i] > 255) {    return false;    }    }    String temp = String.format("%d.%d.%d.%d", parts[0], parts[1], parts[2], parts[3]);    if (count == cs.length  && ! set.contains(temp)) {    ans.add(temp);    set.add(temp);    }    return true;    }}/* * AC * 需要更加简化逻辑，现在的逻辑还是太复杂了. * 11 ms */static class Solution2 {List<String> ans = new LinkedList<String>();int[] ar = null, ch = null;// ar是输入的int[]版，ch是选择的12个数字中的一个int count = 0, arJ = 0, this_count = 0, del_count = 0;HashSet<String> set = new HashSet<>();public List<String> restoreIpAddresses(String s) {if (s == null || s.length() < 4 || s.length() > 12) {    return ans;    }ar = new int[s.length()];ch = new int[12];arJ = ar.length - 1;for (int  i = 0; i < ar.length; i ++) {ar[i] = s.charAt(i) - '0';}Arrays.fill(ch, -1);ch[0] = ar[0];ch[ch.length - 1] = ar[ar.length - 1];int ar_i = 1;int ch_min = 1, ch_max = ch.length - 2;search(ar_i, ch_min, ch_max);return ans;}// [ar_min, ar_max]  [ch_min, ch_max]void search(int ar_i, int ch_min, int ch_max) {if (this_count >= ar.length - 2) {if (judge()) {System.out.printf("第\t%d\t次数据\r\n", del_count ++);tools.Utils.printArray(ar, 20);tools.Utils.printArray(ch, 20);}return;}for (int ch_now = ch_min; ch_now <= ch_max; ch_now ++) {ch[ch_now] = ar[ar_i];this_count ++;search(ar_i + 1, ch_now + 1, ch_max);this_count --;ch[ch_now] = -1;}}boolean judge() {boolean isAllFailue = false;StringBuilder st = new StringBuilder(16);for (int i = 0; ! isAllFailue && i < 4; i ++) {int base = i * 3;if (ch[base + 0] == -1 && ch[base + 1] == -1 && ch[base + 2] == -1) {isAllFailue = true;continue;} else if (ch[base + 0] == 0 && (ch[base + 1] != 0 && ch[base + 1] != -1)) {isAllFailue = true;continue;} else if (ch[base + 0] == 0 && ch[base + 1] == 0 && ch[base + 2] != -1) {isAllFailue = true;continue;}int value = 0;boolean isFirstNot_N_1 = false;for (int j = 0; ! isAllFailue && j < 3; j ++) {if (ch[base + j] != -1) {int temp = value * 10 + ch[base + j];if (!isFirstNot_N_1 || (temp != value && value != 0)) {value = temp;} else {isAllFailue = true;}isFirstNot_N_1 = true;}}if (value < 0 || value > 255) {isAllFailue = true;}st.append(i == 0 ? "" : ".");st.append(value);}if (isAllFailue) {return false;}String now = st.toString();if (! set.contains(now)) {ans.add(now);set.add(now);return true;}return false;}}}

C Solution: github

/*    url: leetcode.com/problems/restore-ip-addresses    AC 0ms 87.50%*/#include <stdio.h>#include <stdlib.h>#include <string.h>typedef char* T;typedef struct al sal;typedef struct al * pal;struct al {    int capacity;    int size;    T* arr;};pal al_init(int capacity) {    pal l = (pal) malloc(sizeof(sal));    if (capacity < 1) return NULL;    l->arr = (T*) malloc(sizeof(T) * capacity);    l->capacity = capacity;    l->size = 0;    return l;}void al_expand_capacity(pal l) {    T* new_arr = (T*) malloc(sizeof(T) * (l->capacity * 2 + 1));    int i = 0;    for (i = 0; i < l->capacity; i ++)        new_arr[i] = l->arr[i];    free(l->arr);    l->arr = new_arr;    l->capacity = l->capacity * 2 + 1;}void al_add_last(pal l, T v) {    if (l->capacity == l->size) al_expand_capacity(l);    l->arr[l->size] = v;    l->size ++;}T* al_convert_to_array_free_l(pal l) {    T* arr = l->arr;    free(l);    return arr;}void al_print(pal l) {    int i = 0;    if (l->size == 0) return;    printf("================\r\n");    for (i = 0; i < l->size; i ++)        printf("%s\r\n", l->arr[i]);    printf("================\r\n");    printf("\r\n");}char* char_copy(char* r, int rn) {    char* copy = (char*) malloc(sizeof(char) * rn);    int i = 0;    for (i = 0; i < rn-1; i ++)        copy[i] = r[i];    copy[rn-1] = '\0';    return copy;}void search(pal l, char* s, int si, int sn, char* r, int ri, int rn, int cnt) {    int v = 0, i = 0;    if (si == sn && ri == rn && cnt == 4) {        al_add_last(l, char_copy(r, rn));        return ;    }    if (si >= sn || ri >= rn || cnt >= 4) return;    for (i = 0; i < 3 && si+i < sn; i ++) {        v = v * 10 + s[si + i] - '0';        if (v > 255) break;        r[ri+i] = s[si+i];        r[ri+i+1] = '.';        search(l, s, si+i+1, sn, r, ri+i+2, rn, cnt+1);        if (i == 0 && v == 0) break;    }} char** restoreIpAddresses(char* s, int* rn) {    pal l = al_init(16);    int sn = s == NULL ? 0 : strlen(s);    char* r = NULL;    if (sn < 4 || sn > 12) return NULL;    r = (char*) malloc(sizeof(char) * (sn + 4));    search(l, s, 0, sn, r, 0, sn+4, 0);    free(r);    *rn = l->size;    return al_convert_to_array_free_l(l);}int main() {    /*        0000            --->  0.0.0.0        00000           --->  NULL        25525511135     --->  [255.255.11.135, 255.255.111.35]        123892398       --->  [123.89.23.98, 123.89.239.8]        255255255255    --->  [255.255.255.255]    */    char* s = "0000";    int rn = 0;    char** a = restoreIpAddresses(s, &rn);    int i = 0;    for (i = 0; i < rn; i ++) {        printf("%s\r\n", a[i]);        free(a[i]);    }    free(a);    return 0;}

Python Solution: github

#coding=utf-8'''    url: leetcode.com/problems/restore-ip-addresses    @author:     zxwtry    @email:      zxwtry@qq.com    @date:       2017年4月23日    @details:    Solution: 48ms 85.48%'''class Solution(object):    def search(self, v, vi, vn, r, ri, rn, a):        if vi == vn and ri == rn:            a.append('%d.%d.%d.%d'%tuple(r))        if vi >= vn or ri >= rn: return        s = 0        for i in range(3):            if i+vi >= vn: break            s = s*10 + v[vi+i]            if i != 0 and s < 10: break            if s > 255: break            r[ri] = s            self.search(v, vi+i+1, vn, r, ri+1, rn, a)            def restoreIpAddresses(self, s):        """        :type s: str        :rtype: List[str]        """        sn = 0 if s == None else len(s)        v = [int(s[i]) for i in range(sn)]        r, a = [0]*4, []        self.search(v, 0, sn, r, 0, 4, a)        return a    if __name__ == "__main__":    m = [            "0000",            "000",            "00000",            "1111",            "9999",            "255255255255",            "19216813130",            "010010",        ]    for s in m:        print(s)        print(Solution().restoreIpAddresses(s))        print("============")

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