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<?php |
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declare(strict_types=1); |
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namespace leetcode; |
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class BombEnemy |
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{ |
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public static function maxKilledEnemies(array $grids): int |
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{ |
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[$res, $m, $n] = [0, count($grids), count($grids[0])]; |
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if ($m <= 0 || $n <= 0) { |
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return $res; |
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} |
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$v1 = $v2 = $v3 = $v4 = array_fill(0, $m, array_fill(0, $n, 0)); |
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for ($i = 0; $i < $m; $i++) { |
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for ($j = 0; $j < $n; $j++) { // 列从上到下 |
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$t = ($j === 0 || $grids[$i][$j] === 'W') ? 0 : $v1[$i][$j - 1]; |
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$v1[$i][$j] = $grids[$i][$j] === 'E' ? $t + 1 : $t; |
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} |
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for ($j = $n - 1; $j >= 0; $j--) { // 列从下到上 |
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$t = ($j === $n - 1 || $grids[$i][$j] === 'W') ? 0 : $v2[$i][$j + 1]; |
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$v2[$i][$j] = $grids[$i][$j] === 'E' ? $t + 1 : $t; |
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} |
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} |
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for ($j = 0; $j < $n; $j++) { |
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for ($i = 0; $i < $m; $i++) { // 行从左到右 |
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$t = ($i === 0 || $grids[$i][$j] === 'W') ? 0 : $v3[$i - 1][$j]; |
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$v3[$i][$j] = $grids[$i][$j] === 'E' ? $t + 1 : $t; |
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} |
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for ($i = $m - 1; $i >= 0; $i--) { // 行从右到左 |
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$t = ($i === $m - 1 || $grids[$i][$j] === 'W') ? 0 : $v4[$i + 1][$j]; |
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$v4[$i][$j] = $grids[$i][$j] === 'E' ? $t + 1 : $t; |
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} |
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} |
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for ($i = 0; $i < $m; $i++) { |
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for ($j = 0; $j < $n; $j++) { |
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if ($grids[$i][$j] === '0') { |
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$res = max($res, $v1[$i][$j] + $v2[$i][$j] + $v3[$i][$j] + $v4[$i][$j]); |
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} |
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} |
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} |
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return $res; |
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} |
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public static function maxKilledEnemies2(array $grids): int |
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{ |
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[$res, $m, $n] = [0, count($grids), count($grids[0])]; |
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if ($m <= 0 || $n <= 0) { |
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return $res; |
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} |
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$col = array_fill(0, $n, 0); |
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for ($i = 0; $i < $m; $i++) { |
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for ($j = 0; $j < $n; $j++) { |
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if ($j === 0 || $grids[$i][$j - 1] === 'W') { |
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$row = 0; |
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for ($k = $j; $k < $n && $grids[$i][$k] !== 'W'; $k++) { |
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$row += $grids[$i][$k] === 'E'; |
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} |
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} |
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if ($i === 0 || $grids[$i - 1][$j] === 'W') { |
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$col[$j] = 0; |
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for ($k = $i; $k < $m && $grids[$k][$j] !== 'W'; $k++) { |
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$col[$j] += $grids[$k][$j] === 'E'; |
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} |
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} |
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if ($grids[$i][$j] === '0') { |
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$res = max($res, $row + $col[$j]); |
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} |
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} |
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} |
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return $res; |
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} |
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} |
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