Mixed-cell-height　circuits　have　prevailed　in　advanced　technology　to　address　various　design　requirements.　Along　with　device　scaling,　complex　minimum-implant-area　(MIA)　constraints　arise　as　an　emerging　challenge　in　modern　circuit　designs,　adding　to　the　difficulties　in　mixed-cell-height　placement.　Existing　MIA-aware　detailed　placement　with　single-row-height　standard　cells　is　insufficient　for　mixed-cell-height　designs:　1)　filler　insertion,　typically　used　to　resolve　MIA　violations,　might　incur　unaffordable　area　and　wirelength　overheads　and　2)　mixed-height-cell　perturbation　could　cause　severe　inter-row　MIA　violations.　This　article　addresses　the　mixed-cell-height　detailed　placement　problem　considering　both　intra-　and　inter-row　MIA　constraints.　We　first　fix　intrarow　violations　by　clustering　violating　mixed-height　cells　of　the　same　threshold　voltage,　and　then　perturb　each　cluster　to　obtain　a　desired　cell　permutation　by　applying　an　efficient,　optimal　dynamic-programming-based　algorithm　for　a　special　case　and　Algorithm　DLX　for　general　ones,　where　a　provably　constant　performance　ratio　for　a　mixed-cell-height　reshaping　problem　can　be　achieved.　With　a　network-flow-based　formulation,　remaining　violating　cells　are　placed　in　appropriate　filler-insertion　positions　to　fix　cell　violations　and　minimize　area.　After　performing　mixed-cell-height　detailed　placement,　we　finally　fix　inter-row　violations　by　shifting　violating　cells　in　minimum　displacement.　Experimental　results　show　that　our　algorithm　can　efficiently　solve　all　MIA　violations　without　any　extra　area　overhead.