复盘:
缺少边界条件判断
图片
判断area和visited的位置错误地提前了
图片
重复make了一维map
图片
没画图
没用测试用例走伪代码和图
没用测试用例走伪代码和图到超出边界的情况
我认为只要走两个测试用例 , 都能发现大部分错误 , 走点心吧
func exist(board [][]byte, word string) bool {
for row, rowdata := range board {
s := Solution{visited: make(map[int]map[int]bool)}
res := false
for col, _ := range rowdata {
res = s.wordSearch(word, 0, len(word)-1, board, col, row)
if res == true {
return true
}
}
}
return false
}
type Solution struct {
visited map[int]map[int]bool
}
func (t *Solution) wordSearch(word string, wordhead int, wordend int, board [][]byte, startcol int, startrow int) bool {
if wordhead == len(word)-1 {
return word[wordhead] == board[startrow][startcol]
}
if board[startrow][startcol] == word[wordhead] {
coord := [][]int{{-1, 0}, {0, 1}, {1, 0}, {0, -1}} //up right down left
if _,ok:=t.visited[startrow];!ok {
t.visited[startrow] = make(map[int]bool)
}
t.visited[startrow][startcol] = true
for _, v := range coord {
newrow := startrow + v[0]
newcol := startcol + v[1]
if inArea(newcol, newrow, board) && !t._visited(newcol, newrow) {
res := t.wordSearch(word, wordhead+1, wordend, board, newcol, newrow)
if res == true {
return true
}
}
}
delete(t.visited[startrow], startcol)
}
return false
}
func inArea(col int, row int, board [][]byte) bool {
return row >= 0 && row <= len(board)-1 && col >= 0 && col <= len(board[0])-1
}
func (t *Solution) _visited(col int, row int) bool {
if _, ok := t.visited[row][col]; ok {
return true
} else {
return false
}
}
definition
search $word range [$wordhead,$wordend] in $board , start from $startcol , $startrow , if found , return true , else false
wordSearch ( word , wordhead , wordend , board , startcol , startrow ) {
if in area and not visted {
if board[startrow][startcol] equal word[wordhead] {
find around with order up right down left
mark board[startrow][startcol] as visited
res = -> wordSearch(word,wordHead+1,wordend,board,newcol,newrow)
if res found , return true
else unmark board[startrow][startcol] as unvisted
continue try another direction
if all direction not found , return false
} else {
return false
}
} else {
return false
}
}
class Solution {
private:
int d[4][2] = {{-1, 0}, {0,1}, {1, 0}, {0, -1}};
int m, n;
vector> visited;
bool inArea(int x, int y){
return x >= 0 && x < m && y >= 0 && y < n;
}
// 从board[startx][starty]开始, 寻找word[index...word.size())
bool searchWord(const vector> &board, const string& word, int index,
int startx, int starty ){
//assert(inArea(startx,starty));
if(index == word.size() - 1)
return board[startx][starty] == word[index];
if(board[startx][starty] == word[index]){
visited[startx][starty] = true;
// 从startx, starty出发,向四个方向寻
for(int i = 0 ; i < 4 ; i ++){
int newx = startx + d[i][0];
int newy = starty + d[i][1];
if(inArea(newx, newy) && !visited[newx][newy] &&
searchWord(board, word, index + 1, newx, newy))
return true;
}
visited[startx][starty] = false;
}
return false;
}
public:
bool exist(vector>& board, string word) {
m = board.size();
assert(m > 0);
n = board[0].size();
assert(n > 0);
visited.clear();
for(int i = 0 ; i < m ; i ++)
visited.push_back(vector(n, false));
for(int i = 0 ; i < board.size() ; i ++)
for(int j = 0 ; j < board[i].size() ; j ++)
if(searchWord(board, word, 0, i, j))
return true;
return false;
}
};