class Solution {
public int minHeightShelves(int[][] books, int shelf_width) {
int n = books.length;
int[] dp = new int[n + 1];
Arrays.fill(dp, Integer.MAX_VALUE);
dp[0] = 0;
for (int i = 1; i <= n; i++) {
int maxHeight = 0;
int widthLeft = shelf_width;
for (int j = i - 1; j >= 0; j--) {
widthLeft -= books[j][0];
maxHeight = Math.max(maxHeight, books[j][1]);
if (widthLeft >= 0) {
dp[i] = Math.min(dp[i], dp[j] + maxHeight);
}
}
}
return dp[n];
}
}