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package class_2022_10_4_week;
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// 来自学员问题
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// 给定一个二维数组matrix
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// 每个格子都是正数，每个格子都和上、下、左、右相邻
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// 你可以从任何一个格子出发，走向相邻的格子
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// 把沿途的数字乘起来，希望得到的最终数字中，结尾的0最多
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// 走的过程中，向左走或者向右走的拐点，最多只能有一次
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// 返回结尾最多的0，能是多少
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// 1 <= 行、列 <= 400
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public class Code02_MostTrailingZerosTurnLeftOfRightAtMostOnce {
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public static int mostTrailingZeros(int[][] matrix) {
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int n = matrix.length;
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int m = matrix[0].length;
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// f2[i][j] : matrix[i][j]自己有几个2的因子
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int[][] f2 = new int[n][m];
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// f5[i][j] : matrix[i][j]自己有几个5的因子
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int[][] f5 = new int[n][m];
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for (int i = 0; i < n; i++) {
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for (int j = 0; j < m; j++) {
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f2[i][j] = factors(matrix[i][j], 2);
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f5[i][j] = factors(matrix[i][j], 5);
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}
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}
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int[][] leftF2 = new int[n][m];
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int[][] leftF5 = new int[n][m];
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int[][] upF2 = new int[n][m];
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int[][] upF5 = new int[n][m];
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for (int i = 0; i < n; i++) {
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for (int j = 0; j < m; j++) {
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leftF2[i][j] = f2[i][j] + (j > 0 ? leftF2[i][j - 1] : 0);
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leftF5[i][j] = f5[i][j] + (j > 0 ? leftF5[i][j - 1] : 0);
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upF2[i][j] = f2[i][j] + (i > 0 ? upF2[i - 1][j] : 0);
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upF5[i][j] = f5[i][j] + (i > 0 ? upF5[i - 1][j] : 0);
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}
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}
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int ans = 0;
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for (int i = 0; i < n; i++) {
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for (int j = 0; j < m; j++) {
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// 来到(i,j)
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int l2 = j == 0 ? 0 : leftF2[i][j - 1];
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int l5 = j == 0 ? 0 : leftF5[i][j - 1];
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int r2 = leftF2[i][m - 1] - leftF2[i][j];
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int r5 = leftF5[i][m - 1] - leftF5[i][j];
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int u2 = i == 0 ? 0 : upF2[i - 1][j];
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int u5 = i == 0 ? 0 : upF5[i - 1][j];
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int d2 = upF2[n - 1][j] - upF2[i][j];
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int d5 = upF5[n - 1][j] - upF5[i][j];
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int p1 = Math.min(l2 + u2 + f2[i][j], l5 + u5 + f5[i][j]);
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int p2 = Math.min(l2 + r2 + f2[i][j], l5 + r5 + f5[i][j]);
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int p3 = Math.min(l2 + d2 + f2[i][j], l5 + d5 + f5[i][j]);
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int p4 = Math.min(u2 + r2 + f2[i][j], u5 + r5 + f5[i][j]);
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int p5 = Math.min(u2 + d2 + f2[i][j], u5 + d5 + f5[i][j]);
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int p6 = Math.min(r2 + d2 + f2[i][j], r5 + d5 + f5[i][j]);
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ans = Math.max(ans, Math.max(Math.max(p1, p2), Math.max(Math.max(p3, p4), Math.max(p5, p6))));
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}
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}
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return ans;
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}
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public static int factors(int num, int f) {
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int ans = 0;
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while (num % f == 0) {
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ans++;
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num /= f;
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}
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return ans;
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}
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public static void main(String[] args) {
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int[][] matrix1 = { { 5, 8, 3, 1 }, { 4, 15, 12, 1 }, { 6, 7, 10, 1 }, { 9, 1, 2, 1 } };
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System.out.println(mostTrailingZeros(matrix1));
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int[][] matrix2 = { { 7500, 10, 11, 12 }, { 6250, 13, 14, 15 }, { 134, 17, 16, 1 }, { 5500, 2093, 5120, 238 } };
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System.out.println(mostTrailingZeros(matrix2));
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}
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}
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