DP 思维好题（转载）

转载自 https://www.luogu.com.cn/discuss/1174071

P3881, P3170, P3179, P3190, P3272, P3290, P3336, P3351, P3600, P3724, P5075, P1721, P1924, P1933, P2145, P3685, P2304, P2289, P2612, P2703, P4365, P4383, P4845, P4827, P3798, P5347, P6690, P6750, P6455, P6849, P4321, P8334, P5565, P6073, P5896, P6385, P6596, P5617, P5642, P7289, P7650, P7155, P7156, P7348, P7879, P7418, P7563, P7564, P7438, P7440,
P13780,
CF2153D,
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P3863,