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class Solution {
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  public int rectangleArea(int[][] rectangles) {
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    int n = rectangles.length;
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    Set<Integer> coorx = new HashSet<>();
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    Set<Integer> coory = new HashSet<>();
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    for (int[] rec : rectangles) {
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      coorx.add(rec[0]);
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      coorx.add(rec[2]);
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      coory.add(rec[1]);
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      coory.add(rec[3]);
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    }
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    Integer[] compressx = coorx.toArray(new Integer[0]);
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    Arrays.sort(compressx);
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    Integer[] compressy = coory.toArray(new Integer[0]);
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    Arrays.sort(compressy);
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    Map<Integer, Integer> mapx = new HashMap<>();
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    for (int i = 0; i < compressx.length; i++) {
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      mapx.put(compressx[i], i);
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    }
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    Map<Integer, Integer> mapy = new HashMap<>();
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    for (int i = 0; i < compressy.length; i++) {
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      mapy.put(compressy[i], i);
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    }
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    boolean[][] grid = new boolean[compressx.length][compressy.length];
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    for (int[] rec : rectangles) {
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      for (int x = mapx.get(rec[0]); x < mapx.get(rec[2]); x++) {
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        for (int y = mapy.get(rec[1]); y < mapy.get(rec[3]); y++) {
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          grid[x][y] = true;
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        }
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      }
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    }
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    long res = 0L;
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    for (int i = 0; i < grid.length; i++) {
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      for (int j = 0; j < grid[0].length; j++) {
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        if (grid[i][j]) {
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          res += (long) (compressx[i + 1] - compressx[i]) * (compressy[j + 1] - compressy[j]);
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        }
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      }
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    }
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    res %= 1000000007;
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    return (int) res;
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  }
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}