珅泽教育CSP-J第一轮模拟考第五套 第 40 题
(5) 处应填（ ）。
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sum(x2, y2) - sum(x2, y1 - 1) - sum(x1 - 1, y2) + sum(x1 - 1, y1 - 1)sum(x2, y2) - sum(x2, y1 + 1) - sum(x1, y2 + 1) + sum(x1 - 1, y1 - 1)sum(x2 - 1, y2 - 1) - sum(x2 - 1, y1) - sum(x1, y2 - 1) + sum(x1, y1)sum(x2 + 1, y2 + 1) - sum(x2 + 1, y1) - sum(x1, y2 + 1) + sum(x1, y1)